• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The first magnetic layer and the second magnetic layer are laminated through the tunnel barrier layer, and the change in the magnetoresistance ratio with respect to the change in the voltage applied so that the second magnetic layer becomes low potential compared with the first magnetic layer is different. It has a small area compared with the change of the magnetoresistance ratio with respect to the change of the voltage applied to become high potential compared with the magnetic layer. In the magnetic tunnel element, by applying a voltage such that the second magnetic layer becomes lower than the first magnetic layer, the voltage dependency of the magnetoresistance ratio decreases, so that a stable tunnel current flows.
    公开号:KR20010023130A
    申请号:KR1020007001752
    申请日:1999-06-22
    公开日:2001-03-26
    发明作者:세이지 구마가이；준이찌 혼다；요시또 이께다
    申请人:이데이 노부유끼；소니 가부시끼 가이샤；
    IPC主号:
    专利说明:

    MAGNETIC TUNNEL DEVICE, METHOD OF MANUFACTURE THEREOF, AND MAGNETIC HEAD
    Conventionally, in a layer structure in which a thin insulating layer is sandwiched by a pair of magnetic metal layers, when a pair of magnetic metal layers is applied as an electrode, the conductance of the tunnel current flowing through the insulating layer causes the magnetization of the pair of magnetic metal layers. Magnetic tunneling effects have been reported to vary depending on the relative angles. That is, in the layer structure formed by sandwiching a thin insulating layer with a pair of magnetic metal layers, the magnetoresistive effect on the tunnel current flowing through the insulating layer is exhibited.
    In this magnetic tunneling effect, the magnetoresistance ratio can be theoretically calculated from the polarization rate of the magnetization of the pair of magnetic metal layers. In particular, when Fe is used in the pair of magnetic metal layers, a magnetoresistance ratio of about 40% can be expected. There is a number.
    For this reason, a magnetic tunnel element having a layer structure formed by sandwiching a thin insulating layer with at least a pair of magnetic metal layers has attracted attention as an element for external magnetic field detection.
    By the way, in the magnetic tunnel element mentioned above, it is common to use a metal oxide as a thin insulating layer. However, when a metal oxide is used as the insulating layer, pinholes or the like may be formed to cause a short circuit between the pair of magnetic metal layers. In addition, when a metal oxide is used as the insulating layer, the oxidation degree of the metal is insufficient, the tunnel barrier is incomplete, and the magnetic tunneling effect may not be exhibited.
    <Start of invention>
    Accordingly, the present invention has been proposed in view of such a situation, and an object thereof is to provide a magnetic tunnel element, a manufacturing method, and a magnetic head in which tunnel current flows reliably in the tunnel barrier layer and exhibits a stable magnetic tunneling effect. ,
    In the magnetic tunnel device according to the present invention, in a magnetic tunnel device in which a first magnetic layer and a second magnetic layer are laminated through a tunnel barrier layer, a voltage applied so that the second magnetic layer has a low potential compared to the first magnetic layer. The change in the magnetoresistance ratio with respect to the change of is characterized in that the second magnetic layer has a small area compared to the change in the magnetoresistance ratio with respect to the change in voltage applied so that the second magnetic layer becomes high potential compared with the first magnetic layer. will be.
    In the magnetic tunnel device according to the present invention configured as described above, electrons flow from the second magnetic layer toward the first magnetic layer through the tunnel barrier layer by applying a voltage such that the second magnetic layer has a low potential as compared with the first magnetic layer. . At this time, in the magnetic tunnel element, the amount of change in the magnetoresistance ratio is smaller than in the case where electrons are flowed in the reverse direction. In other words, by applying a voltage such that the second magnetic layer becomes low in comparison with the first magnetic layer, in the magnetic tunnel element, the voltage dependency of the magnetoresistance ratio is reduced. For this reason, in the magnetic tunnel element, stable tunnel current flows in the tunnel barrier layer regardless of the magnitude of the voltage.
    In addition, the magnetic tunnel device according to the present invention includes a tunnel barrier layer formed on a first magnetic layer, the first magnetic layer, and having an increased oxidation degree from the first magnetic layer side, and a tunnel barrier layer formed on the tunnel barrier layer. And a second magnetic layer, wherein a tunnel current flows through the tunnel barrier layer by supplying electrons from the second magnetic layer toward the first magnetic layer.
    In the magnetic tunnel element according to the present invention configured as described above, a tunnel barrier layer is formed by oxidizing a metal stepwise on the first magnetic layer. In other words, the tunnel barrier layer having the lowest oxidation degree is formed on the first magnetic layer. For this reason, the tunnel barrier layer has good adhesion to the first magnetic layer. In addition, this magnetic tunnel element defines the supply direction of electrons to the tunnel barrier layer. For this reason, in this magnetic tunnel element, stable tunnel current flows in the tunnel barrier layer regardless of the magnitude of the voltage.
    Further, in the method for manufacturing a magnetic tunnel element according to the present invention, a tunnel barrier layer is formed by forming a first magnetic layer, and stepwise oxidizing a metal on the first magnetic layer, and through the tunnel barrier layer, The second magnetic layer is formed on the first magnetic layer.
    According to the method of manufacturing the magnetic tunnel element according to the present invention configured as described above, since the tunnel barrier layer is formed by oxidizing the metal stepwise, the adhesion of the tunnel barrier layer to the first magnetic layer can be improved. In addition, in this technique, since the tunnel barrier layer is formed by oxidizing the metal in stages, it is possible to manufacture a magnetic tunnel element through which tunnel current flows stably regardless of the magnitude of the voltage.
    In addition, the magnetic head according to the present invention is formed by stacking a first magnetic layer and a second magnetic layer through a tunnel barrier layer, and is applied to a change in voltage applied so that the second magnetic layer has a low potential compared to the first magnetic layer. A magnetic tunnel element having a small area compared with a change in magnetoresistance ratio with respect to a change in voltage applied so that the change in the magnetoresistance ratio with respect to the voltage applied to the second magnetic layer becomes high with respect to the first magnetic layer, The magnetic tunnel element is characterized by a potato portion.
    In the magnetic head according to the present invention configured as described above, a voltage is applied to the magnetic tunnel element such that the second magnetic layer is at a low potential compared with the first magnetic layer, so that the second magnetic layer is directed from the second magnetic layer to the first magnetic layer through the tunnel barrier layer. Shed electrons. At this time, in the magnetic tunnel element, the amount of change in the magnetoresistance ratio is smaller than in the case where electrons are flowed in the reverse direction. In other words, by applying a voltage such that the second magnetic layer becomes low in comparison with the first magnetic layer, in the magnetic tunnel element, the voltage dependency of the magnetoresistance ratio is reduced. For this reason, in the magnetic head, the magnetic tunnel element serving as the potato portion operates stably.
    In addition, the magnetic head according to the present invention includes a first magnetic layer, a tunnel barrier layer formed on the first magnetic layer and having an increased oxidation degree from the first magnetic layer side, and a second barrier layer formed on the tunnel barrier layer. And a magnetic tunnel element having a magnetic layer and flowing a tunnel current through the tunnel barrier layer by supplying electrons from the second magnetic layer to the first magnetic layer, wherein the magnetic tunnel element is a potato portion.
    In the magnetic head according to the present invention configured as described above, the magnetic tunnel element in which the tunnel barrier layer is formed by stepwise oxidizing a metal on the first magnetic layer is a potato portion. That is, in the magnetic tunnel element, the tunnel barrier layer having the lowest oxidation degree is formed on the first magnetic layer. For this reason, the tunnel barrier layer has good adhesion to the first magnetic layer. In addition, this magnetic head defines the direction of supply of electrons to the tunnel barrier layer. For this reason, in this magnetic head, stable tunnel current flows with respect to the tunnel barrier layer regardless of the magnitude | size of a voltage, and the magnetic tunnel element which is a potato part operates stably.
    In the present invention, a pair of magnetic layers are laminated through a tunnel barrier layer, and a tunnel current flows from one magnetic layer to another magnetic layer, and the conductance of the tunnel current varies depending on the polarization rate of magnetization of the pair of magnetic layers. An element, a manufacturing method thereof, and a magnetic head are provided.
    1 is a perspective view of an essential part of a magnetic tunnel element shown as an example;
    2 is an essential part cross sectional view of the magnetic tunnel element;
    Fig. 3 is a characteristic diagram showing the relationship between the voltage and the normalized magnetoresistance ratio in the magnetic tunnel element.
    4 is a perspective view of an essential part of a magnetic tunnel element connecting a constant current source and a voltmeter;
    5 is a characteristic diagram showing a voltage and a resistance value and a magnetoresistance ratio applied to the magnetic tunnel element.
    6 is a conceptual diagram schematically showing a tunnel barrier in a magnetic tunnel element.
    7 is a characteristic diagram showing a voltage, a resistance value, and a magnetoresistance ratio applied to a magnetic tunnel element formed without performing annealing.
    <The best form to perform invention>
    EMBODIMENT OF THE INVENTION Hereinafter, the best form of the magnetic tunnel element, its manufacturing method, and magnetic head which concern on this invention is demonstrated in detail with reference to drawings.
    As shown in FIG. 1, the magnetic tunnel element includes a first magnetic metal layer 2 formed in a band shape on a nonmagnetic substrate 1 and a tunnel formed so as to cover a substantially central portion of the first magnetic metal layer 2. The barrier layer 3 and the second magnetic metal layer 4 formed on the tunnel barrier layer 3 are provided. In this magnetic tunnel element, the first magnetic metal layer 2 and the second magnetic metal layer 4 are formed so that their respective longitudinal directions are substantially orthogonal to each other. For this reason, in this magnetic tunnel element, the 1st magnetic metal layer 2 and the 2nd magnetic metal layer 4 are laminated | stacked through the tunnel barrier layer 3 from each substantially center part.
    FIG. 2 is a cross-sectional view of a portion in which the first magnetic metal layer 2 and the second magnetic metal layer 4 in the magnetic tunnel element are laminated via the tunnel barrier layer 3. As shown in FIG. 2, the first magnetic metal layer 2 has a two-layer structure formed by sequentially stacking the NiFe layer 5 and the Co layer 6 from the nonmagnetic substrate 1 side. The second magnetic electrode layer 4 is a four-layer structure formed by sequentially stacking a Co layer 7, a NiFe layer 8, a FeMn layer 9, and a Ta layer 10 from the tunnel barrier layer 3 side. It was set as.
    Specifically, as the nonmagnetic substrate 1, a Si (100%) substrate obtained by oxidizing the surface to 3000 Pa was used.
    In the first magnetic metal layer 2, the NiFe film 5 is a magnetization free film having a low coercive force and changing its magnetization direction with respect to an external magnetic field. In this first magnetic metal layer 2, the Co layer 6 is a layer arranged to increase the spin polarization rate together with the Co layer 7 described later. That is, the magnetic tunnel is arranged by arranging the interface between the NiFe film 5 and the tunnel barrier layer 3, the interface between the NiFe 9 and the tunnel barrier layer 3, and the Co layer 6 and the Co layer 7. The magnetoresistance ratio of the device can be increased.
    Specifically, the NiFe film 5 is formed on the nonmagnetic substrate 1 described above with a film thickness of 188 kV, and the Co film 6 is formed on the NiFe film 5 with a film thickness of 33 kPa. In addition, these NiFe films 5 and Co films 6 were formed into a band by sputtering using a metal mask.
    The first magnetic metal layer 2 is subjected to a so-called annealing treatment. This annealing treatment was performed in a vacuum of 6 × 10 −4 pa at 350 ° C. while applying a magnetic field of 330 Oe in the longitudinal direction of the first magnetic metal film 2.
    The tunnel barrier layer 3 is a layer in which the degree of oxidation increases from the side of the first magnetic metal layer 2 by oxidizing the metal in stages. This tunnel barrier layer 3 serves as an electrical barrier between the first magnetic metal layer 2 and the second magnetic metal layer 4 to form a so-called tunnel barrier.
    The tunnel barrier layer 3 is formed using a metal such as Al, Gd, Hf, Fe, Co, Ni, Se, Mg, or the like. However, the tunnel barrier layer 3 is not limited to these metal elements, and any metal may be used as long as it can be a tunnel barrier by being oxidized.
    When the tunnel barrier layer 3 is formed, a metal element may be formed on the first magnetic metal layer 2 formed as described above with increasing oxygen partial pressure. By increasing the oxygen partial pressure in this manner, the tunnel barrier layer 3 is formed so as to increase the oxidation degree from the first magnetic metal layer 2 side.
    Specifically, a mixed gas of Ar and O 2 can be used as a process gas for forming the tunnel barrier layer 3. Under the mixed gas atmosphere of Ar and O 2 , the tunnel barrier layer 3 can be formed by forming the metal for 60 seconds. At the start of film formation, the partial pressure ratio in the mixed gas is set to Ar: O 2 = 10: 0, and after 60 seconds, the oxygen partial pressure is directly increased so that the partial pressure ratio is Ar: O 2 = 10: 1. I was.
    In addition, in the above-described method, the oxygen partial pressure is directly increased to form the tunnel barrier layer 3 by oxidizing the metal stepwise, but the present invention is not limited to this method. In other words, in order to oxidize the metal stepwise, the oxygen partial pressure may be increased exponentially.
    In the second magnetic metal layer 4, the FeMn layer 9 is an antiferromagnetic material and fixes the magnetization of the NiFe layer 8 in a predetermined direction. By this FeMn layer 9, the NiFe layer 8 becomes a magnetized pinned film. In the second magnetic metal layer 4, the Co layer 7 is a layer arranged to improve the magnetoresistance ratio of the magnetic tunnel element as described above. In the second magnetic metal layer 4, the Ta layer 10 is a layer arranged to prevent corrosion of the FeMn layer 9.
    Specifically, the film thickness of the Co layer 7 is 26 kPa, the film thickness of the NiFe layer 8 is 188 kPa, the film thickness of the FeMn layer 9 is 450 kPa, and the film of the Ta layer 10 is In order to make thickness 200Å, it formed in strip form by sputtering using a metal mask in order. At this time, each layer was formed, applying a 52Oe magnetic field in the direction orthogonal to a longitudinal direction.
    Moreover, Ar gas was used as a process at the time of sputtering each layer. In the case of forming each layer, the Ar gas pressure is 0.3 Pa for NiFe films 5 and 8 and Co (6 and 7) films, 0.2 Pa for Al, and FeMn film 9 It was 0.6 Pa.
    Specifically, as the area of the portion where the first magnetic metal layer 2 and the second magnetic metal layer 4 overlap, that is, the area of the portion through which the tunnel current flows, nine types of 100 × 100 to 500 × 50 μm 2 are used. Was produced.
    In the magnetic tunnel element constructed as described above, when an external magnetic field is applied, the magnetization direction of the NiFe film 5 in the first magnetic metal layer 2 changes. In contrast, in the second magnetic metal layer 4, even if an external magnetic field is applied, the magnetization direction is not changed. Therefore, when an external magnetic field is applied to the magnetic tunnel element, the relative angle between the magnetization direction of the NiFe film 5 and the magnetization direction of the NiFe film 8 changes.
    When the relative angle between the magnetization direction of the NiFe film 5 and the magnetization direction of the NiFe film 8 changes, the resistance value against the tunnel current flowing to the tunnel barrier layer 3 changes. In other words, the resistance value against the tunnel current flowing through the tunnel barrier layer 3 changes depending on the relative angle between the magnetization direction of the NiFe film 5 and the magnetization direction of the NiFe film S. Therefore, in the magnetic tunnel element, a predetermined tunnel current flows through the tunnel barrier layer 3 and the voltage value of the tunnel current is detected, whereby a change in resistance value with respect to the tunnel current can be detected as a voltage change. That is, in the tunnel element, the external magnetic field can be detected by detecting the voltage change of the tunnel current.
    In particular, in this magnetic tunnel element, the second magnetic metal layer 4 is the first magnetic metal layer, as opposed to the case where the second magnetic metal layer 4 is applied at a low potential compared with the first magnetic metal layer 2. In the case of applying a voltage so as to have a high potential as compared with (2), the amount of change in the magnetoresistance ratio with respect to the voltage change is different. In the following description, the voltage applied so that the second magnetic metal layer 4 becomes low in comparison with the first magnetic metal layer 2 is referred to as "plus voltage", and on the contrary, the second magnetic metal layer 4 is The voltage applied so that it becomes high electric potential compared with the 1 magnetic metal layer 2 is called "minus voltage."
    In this magnetic tunnel element, as shown in Fig. 3, the amount of change in the magnetoresistance ratio with respect to the change in the positive voltage is smaller than the amount of change in the magnetoresistance ratio with respect to the change in the negative voltage. In other words, when a positive voltage is applied, there is a region in the magnetic tunnel element in which the magnetoresistance ratio shows a substantially constant value regardless of the voltage change.
    3, the vertical axis represents the value obtained by dividing the maximum magnetoresistance ratio by the magnetoresistance ratio at a predetermined voltage value (represented by "standardized MR ratio"). The horizontal axis represents the magnetic tunnel element. The magnitude | size of the voltage (plus voltage made positive and minus voltage became negative.) Applied with respect to is shown.
    This magnetic tunnel element is driven in a region in which the magnetoresistance ratio is usually shown at a constant value without depending on the voltage change, thereby exhibiting a stable magnetic tunneling effect. In other words, in this magnetic tunnel element, electrons are flown from the second magnetic metal layer 4 to the first magnetic metal layer 2, so that the magnetoresistance ratio is stable regardless of the change in the voltage, so that the magnetic tunnel element operates stably. You can do it. Specifically, as can be seen from FIG. 3, by applying a positive voltage of 0 to 50 mA, the magnetic tunnel element can change the magnetoresistance ratio within 1%. Therefore, the magnetic tunnel element can be stably operated by being driven at a positive voltage of 0 to 50 mA.
    In this magnetic tunnel element, it is preferable that the change in the magnetoresistance ratio at least in the range of 0 to 1.25 mA of the positive voltage is within 1%. In other words, in the magnetic tunnel element, the maximum value of the positive voltage at which the change in the magnetoresistance ratio is within 1% is preferably 1.25 mA or more.
    For example, when a magnetic tunnel element using Fe exhibiting a magnetoresistance ratio of about 40% is used, it is necessary to set the driving voltage to 1.25 kV in order to obtain a voltage change output of 0.5 mW. In other words, when the maximum value of the positive voltage at which the change in the magnetoresistance ratio is less than 1% is less than 1.25 kV, there is a possibility that a sufficient voltage change output cannot be obtained by using the magnetic tunnel element having the magnetoresistance ratio of about 40%.
    This magnetic tunnel element is preferably used for, for example, a magnetic head for reproducing a signal recorded on a magnetic recording medium. In other words, as the magnetic head, it is preferable to use the above-mentioned magnetic tunnel element as the potato portion for detecting the magnetic field from the magnetic recording medium. In this magnetic head, the magnetic field from the magnetic recording medium can be stably detected by applying a positive voltage to the magnetic tunnel element.
    In addition, the magnetic tunnel element is preferably used as a magnetic head for a magnetic recording medium of high density recording because the magnetoresistance ratio is larger than that of an ordinary anisotropic magnetoresistive element or a giant magnetoresistive element. In other words, the magnetic head can reliably reproduce the high density recorded magnetic recording medium by using the magnetic tunnel element as the potato portion.
    By the way, in the above-described magnetic tunnel element, the magnetoresistance ratio is usually constant without applying a positive voltage and depending on the voltage change. This is because in the magnetic tunnel element, the tunnel barrier layer 3 is formed so that the oxidation degree is increased from the first magnetic metal layer 2 side by oxidizing the metal in stages.
    By applying a positive voltage to the tunnel barrier layer 3 as described above, electrons are supplied from the high oxidation side. In other words, this magnetic tunnel element stably exhibits the magnetic tunneling effect by supplying electrons from the second magnetic metal layer 4 side with high oxidation degree.
    In order to verify this, for the magnetic tunnel element as described above, as shown in FIG. 4, between the constant current source for supplying a predetermined current and the first magnetic metal layer 2 and the second magnetic metal layer 4 A voltmeter for measuring the voltage was connected, and the supply direction of the electrons was changed to measure the resistance value and the magnetoresistance ratio.
    At this time, the case of supplying electrons from the first magnetic metal layer 2 toward the second magnetic metal layer 4 is called "-direction", and on the contrary, from the second magnetic metal layer 4 to the first magnetic metal layer 2. The case of supplying electrons toward the side is called "+ direction". And a voltmeter was connected so that it might show minus when electrons were supplied in the "-direction", and it would show plus when electrons were supplied in the "+ direction".
    For the magnetic tunnel element constructed as described above, an external magnetic field in a constant direction was applied, and the change in resistance value and the change in magnetoresistance ratio when the voltage was changed were measured. The result is shown in FIG.
    As is apparent from FIG. 5, when electrons are supplied in the − direction, the resistance value changes as the voltage increases. In other words, when electrons are supplied in the − direction, the resistance of the tunnel barrier layer 3 has a voltage dependency that varies with the voltage value.
    On the other hand, in the case where electrons are supplied in the + direction, the resistance value is substantially constant even if the applied voltage increases. This indicates that the tunnel barrier layer 3 has no voltage dependency when electrons are supplied in the + direction. As shown in Fig. 5, since an external magnetic field in a constant direction is applied, the magnetoresistance ratio is constant. In addition, FIG. 3 mentioned above is produced using the value of the magnetoresistance ratio in this FIG.
    From this point of view, in the case of having the tunnel barrier layer 3 formed by increasing the oxidation degree from the first magnetic metal layer 2 side, by supplying electrons in the + direction, the magnetic tunnel element has a stable magnetic tunnel without voltage dependence. It has been proved to show the effect. This is because the portion of the second magnetic metal layer 4 side in the tunnel barrier layer 3 is most oxidized, so that the potential of the tunnel barrier in the thickness direction of the tunnel barrier layer 3 is shown in FIG. It is considered because it is comprised as follows.
    In the above-described magnetic tunnel element, the oxygen partial pressure is gradually increased to form the tunnel barrier layer 3. For this reason, in this magnetic tunnel element, the tunnel barrier layer 3 becomes excellent in adhesiveness to the first magnetic metal layer 2. Therefore, in this magnetic tunnel element, the tunnel barrier layer 3 is peeled off from the first magnetic metal layer 2, or the first magnetic metal layer 2 and the second magnetic metal layer 4 are short-circuited through the pinhole. That is reliably prevented. As a result, in this magnetic tunnel element, the tunnel current always stably flows.
    By the way, in this magnetic tunnel element, annealing process is performed as mentioned above. This annealing treatment is performed under temperature conditions or magnetic field conditions determined in consideration of magnetoresistance ratio, soft magnetic properties, magnetic stability, and the like. Therefore, the magnetic tunnel element exhibits the desired magnetoresistance ratio and soft magnetic characteristics by performing this annealing treatment.
    On the other hand, in the magnetic tunnel element formed without performing the annealing process, the resistance value change and the magnetoresistance ratio change when the voltage is changed in the state in which the external magnetic field is applied in a predetermined direction are made as shown in FIG. As shown in Fig. 7, in the case where the annealing process is not performed, even if electrons are supplied in either the + direction or the − direction, the dependence on the voltage is not seen.
    From this, it can be seen that it is effective to supply electrons from the second magnetic metal layer 4 toward the first magnetic metal layer 2 to the magnetic tunnel element subjected to the annealing treatment as described above.
    In the magnetic tunnel device described above, by applying a positive voltage, the magnetoresistance ratio does not have a voltage dependency and usually shows a constant value. However, the present invention is not limited to this, but for example, a magnet having a region where the amount of change in the magnetoresistance ratio with respect to the change in the negative voltage is smaller than the amount of change in the magnetoresistance ratio with respect to the change in the positive voltage. The same applies to tunnel elements. That is, in this case, by applying a negative voltage to the magnetic tunnel element and supplying electrons from the first magnetic metal layer 2 to the second magnetic metal layer 4, the magnetoresistance ratio is usually one without depending on the voltage change. It represents politics. Therefore, in this magnetic tunnel element, the magnetic tunnel effect can be stably exhibited by applying a negative voltage.
    As described above, in the magnetic tunnel device according to the present invention, the voltage dependency of the magnetoresistance ratio is reduced by applying a voltage such that the second magnetic layer is at a low potential as compared with the first magnetic layer. For this reason, in the magnetic tunnel element, a stable tunnel current flows regardless of the magnitude of the voltage to the tunnel barrier layer, so that the magnetic tunnel effect can always be stably exhibited.
    In addition, in the magnetic tunnel device according to the present invention, a tunnel barrier layer is formed on the first magnetic layer and has an increased oxidation degree from the first magnetic layer side, and supplies electrons from the second magnetic layer toward the first magnetic layer. have. For this reason, in this magnetic tunnel element, a stable magnetic tunnel effect can be exhibited regardless of the magnitude of the voltage applied. Moreover, in this magnetic tunnel element, since the adhesion surface with the 1st magnetic layer in an insulating layer has the lowest oxidation degree, the adhesiveness of a 1st magnetic layer and an insulating layer becomes favorable. Therefore, this magnetic tunnel element can always stably exhibit the magnetic tunnel effect.
    Further, in the method for manufacturing the magnetic tunnel element according to the present invention, since the tunnel barrier layer is formed by oxidizing the metal in stages, the adhesion of the tunnel barrier layer to the first magnetic layer can be improved. In addition, in this technique, since the tunnel barrier layer is formed by oxidizing the metal in stages, it is possible to manufacture a magnetic tunnel element through which tunnel current flows stably regardless of the magnitude of the voltage. For this reason, according to this method, it is possible to reliably manufacture a magnetic tunnel element that always stably exhibits a magnetic tunnel effect.
    Further, in the magnetic head according to the present invention, the voltage dependence of the magnetoresistance ratio in the magnetic tunnel element is reduced by applying a voltage to the magnetic tunnel element so that the second magnetic layer is lower than the first magnetic layer so as to have a low potential. For this reason, in the magnetic head, the magnetic tunnel element serving as the potato portion can operate stably and exhibit stable electron conversion characteristics.
    权利要求:
    Claims (19)
    [1" claim-type="Currently amended] In a magnetic tunnel device formed by stacking a first magnetic layer and a second magnetic layer through a tunnel barrier layer,
    The change in the magnetoresistance ratio with respect to the change in the voltage applied so that the second magnetic layer becomes low potential compared to the first magnetic layer is equal to the change in the magnetoresistance of the voltage applied so that the second magnetic layer becomes high potential compared to the first magnetic layer. A magnetic tunnel element, characterized in that it has a small area compared with the change in the magnetoresistance ratio to the change.
    [2" claim-type="Currently amended] 2. The magnetic tunnel element according to claim 1, wherein the maximum value of the voltage applied so that the second magnetic layer has a low potential compared with the first magnetic layer such that the change in the magnetoresistance ratio is within 1% is 1.25 kV or more. .
    [3" claim-type="Currently amended] The magnetic layer of claim 1, wherein the first magnetic layer includes a magnetization free layer that changes the magnetization direction according to at least an external magnetic field, and the second magnetic layer includes a magnetized pinned layer having a fixed magnetization in at least a predetermined direction. Magnetic tunnel element.
    [4" claim-type="Currently amended] 2. The magnetization layer of claim 1, wherein the first magnetic layer includes a magnetized pinned layer in at least a predetermined direction, and the second magnetic layer includes a magnetization free layer that changes the magnetization direction in accordance with at least an external magnetic field. 3. Magnetic tunnel element.
    [5" claim-type="Currently amended] The magnetic tunnel element according to claim 1, wherein the annealing treatment is performed at a temperature of 200 캜 to 350 캜.
    [6" claim-type="Currently amended] The first magnetic layer,
    A tunnel barrier layer formed on the first magnetic layer and formed by increasing an oxidation degree from the first magnetic layer side;
    A second magnetic layer formed on the tunnel barrier layer,
    And a tunnel current flowing through the tunnel barrier layer by supplying electrons from the second magnetic layer toward the first magnetic layer.
    [7" claim-type="Currently amended] The magnetic layer of claim 6, wherein the first magnetic layer includes a magnetization free layer that changes the magnetization direction in accordance with at least an external magnetic field, and the second magnetic layer includes a magnetized pinned layer in at least a predetermined direction. Magnetic tunnel element.
    [8" claim-type="Currently amended] 7. The magnetostatic layer of claim 6, wherein the first magnetic layer includes a magnetized pinned layer in at least a predetermined direction, and the second magnetic layer includes a magnetization free layer that changes the magnetization direction in accordance with at least an external magnetic field. Magnetic tunnel element.
    [9" claim-type="Currently amended] The magnetic tunnel element according to claim 6, wherein the annealing treatment is performed at a temperature of 200 deg. C to 350 deg.
    [10" claim-type="Currently amended] Forming a first magnetic layer,
    On the first magnetic layer, a tunnel barrier layer is formed by stepwise oxidizing a metal,
    Through this tunnel barrier layer, a second magnetic layer is formed on the first magnetic layer.
    [11" claim-type="Currently amended] The first magnetic layer and the second magnetic layer are laminated through the tunnel barrier layer, and the change in the magnetoresistance ratio with respect to the change in voltage applied to the second magnetic layer to have a low potential compared with the first magnetic layer is the second. A magnetic tunnel element having a small area compared with the change in the magnetoresistance ratio to the change in voltage applied so that the magnetic layer has a high potential compared with the first magnetic layer,
    A magnetic head comprising the magnetic tunnel element as a potato portion.
    [12" claim-type="Currently amended] 12. The magnetic head as set forth in claim 11, wherein the maximum value of the voltage applied so that the second magnetic layer has a low potential compared with the first magnetic layer such that the change in the magnetoresistance ratio is within 1% is 1.25 kV or more.
    [13" claim-type="Currently amended] 12. The method of claim 11, wherein the first magnetic layer has a magnetization free layer for changing the magnetization direction according to at least an external magnetic field, and the second magnetic layer has a magnetized pinned layer in at least a predetermined direction. Magnetic head.
    [14" claim-type="Currently amended] 12. The method of claim 11, wherein the first magnetic layer includes a magnetized pinned layer in at least a predetermined direction, and the second magnetic layer includes a magnetization free layer that changes the magnetization direction in accordance with at least an external magnetic field. Magnetic head.
    [15" claim-type="Currently amended] 12. The magnetic head as set forth in claim 11, wherein annealing is performed at a temperature of 200 deg. C to 350 deg.
    [16" claim-type="Currently amended] A first magnetic layer, a tunnel barrier layer formed on the first magnetic layer and having an increased oxidation degree from the first magnetic layer side, and a second magnetic layer formed on the tunnel barrier layer; A magnetic tunnel element configured to supply tunnel current to the tunnel barrier layer by supplying electrons toward a first magnetic layer,
    A magnetic head comprising the magnetic tunnel element as a potato portion.
    [17" claim-type="Currently amended] 17. The method of claim 16, wherein the first magnetic layer includes a magnetization free layer that changes the magnetization direction in accordance with at least an external magnetic field, and the second magnetic layer includes a magnetized pinned layer in at least a predetermined direction. Magnetic head.
    [18" claim-type="Currently amended] 17. The method of claim 16, wherein the first magnetic layer includes a magnetized pinned layer in at least a predetermined direction, and the second magnetic layer includes a magnetization free layer that changes the magnetization direction in accordance with at least an external magnetic field. Magnetic head.
    [19" claim-type="Currently amended] 17. The magnetic head as set forth in claim 16, wherein annealing is performed at a temperature of 200 deg. C to 350 deg.
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    同族专利:
    公开号 | 公开日
    JP3896789B2|2007-03-22|
    CN1274475A|2000-11-22|
    WO1999067828A1|1999-12-29|
    CN1166015C|2004-09-08|
    KR100572953B1|2006-04-24|
    US6452892B1|2002-09-17|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1998-06-22|Priority to JP17519798
    1998-06-22|Priority to JP1998-175197
    1999-06-22|Application filed by 이데이 노부유끼, 소니 가부시끼 가이샤
    1999-06-22|Priority to PCT/JP1999/003327
    2001-03-26|Publication of KR20010023130A
    2006-04-24|Application granted
    2006-04-24|Publication of KR100572953B1
    优先权:
    申请号 | 申请日 | 专利标题
    JP17519798|1998-06-22|
    JP1998-175197|1998-06-22|
    PCT/JP1999/003327|WO1999067828A1|1998-06-22|1999-06-22|Magnetic tunnel device, method of manufacture thereof, and magnetic head|
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