MgO-based tunnel spin injectors
First Claim
1. A device, comprising:
- a first layer that includes at least one magnetic material from the group consisting of ferromagnetic materials and ferrimagnetic materials;
a MgO tunnel barrier in contact with the first layer; and
a second layer that includes semiconductor material, the second layer being in contact with the MgO tunnel barrier, the MgO tunnel barrier being sandwiched between the first layer and the second layer, thereby forming a first spintronic element, wherein the first layer, the MgO tunnel barrier, and the second layer are configured to enable spin-polarized charge carrier transport between the semiconductor material and the magnetic material, wherein each of the MgO tunnel barrier and the semiconductor material is crystalline, and wherein the first layer, the MgO tunnel barrier, and the second layer are configured so that, upon application of a voltage across the device, the spin polarization of charge carriers flowing between the MgO tunnel barrier and the semiconductor material is greater than 20%.
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Accused Products
Abstract
A MgO tunnel barrier is sandwiched between semiconductor material on one side and a ferri- and/or ferromagnetic material on the other side to form a spintronic element. The semiconductor material may include GaAs, for example. The spintronic element may be used as a spin injection device by injecting charge carriers from the magnetic material into the MgO tunnel barrier and then into the semiconductor. Similarly, the spintronic element may be used as a detector or analyzer of spin-polarized charge carriers by flowing charge carriers from the surface of the semiconducting layer through the MgO tunnel barrier and into the (ferri- or ferro-) magnetic material, which then acts as a detector. The MgO tunnel barrier is preferably formed by forming a Mg layer on an underlayer (e.g., a ferromagnetic layer), and then directing additional Mg, in the presence of oxygen, towards the underlayer.
146 Citations
98 Claims
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1. A device, comprising:
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a first layer that includes at least one magnetic material from the group consisting of ferromagnetic materials and ferrimagnetic materials; a MgO tunnel barrier in contact with the first layer; and a second layer that includes semiconductor material, the second layer being in contact with the MgO tunnel barrier, the MgO tunnel barrier being sandwiched between the first layer and the second layer, thereby forming a first spintronic element, wherein the first layer, the MgO tunnel barrier, and the second layer are configured to enable spin-polarized charge carrier transport between the semiconductor material and the magnetic material, wherein each of the MgO tunnel barrier and the semiconductor material is crystalline, and wherein the first layer, the MgO tunnel barrier, and the second layer are configured so that, upon application of a voltage across the device, the spin polarization of charge carriers flowing between the MgO tunnel barrier and the semiconductor material is greater than 20%. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A device, comprising:
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a first layer that includes at least one magnetic material from the group consisting of ferromagnetic materials and ferrimagnetic materials, the first layer having a surface that is substantially free of oxide formed from the first layer; a MgO tunnel barrier in contact with the surface of the first layer; and a second layer that includes semiconductor material, the second layer having a surface that is in contact with the MgO tunnel barrier, the MgO tunnel barrier being sandwiched between the first layer and the second layer, wherein the MgO tunnel barrier and the semiconductor material are lattice-matched, each of the MgO tunnel barrier and the semiconductor material being crystalline. - View Dependent Claims (36, 37, 38, 39, 40)
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41. A method, comprising:
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forming a MgO tunnel barrier on a surface of an underlayer, wherein the surface is selected to be substantially free of oxide; and forming an overlayer on the MgO tunnel barrier to construct a spintronic element, with one of the underlayer and the overlayer including a layer of semiconductor material, and the other of the underlayer and the overlayer including a layer of magnetic material selected from the group consisting of ferromagnetic materials and ferrimagnetic materials, wherein the MgO tunnel barrier is sandwiched between the underlayer and the overlayer, wherein the MgO tunnel barrier and the semiconductor material are formed so that they are lattice-matched, and each of the MgO tunnel barrier and the semiconductor material is crystalline. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
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56. A device, comprising:
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a magnetic layer comprising at least one magnetic material from the group consisting of ferromagnetic materials and ferrimagnetic materials; a MgO tunnel barrier; and a semiconducting layer, wherein the MgO tunnel barrier is between the magnetic layer and the semiconducting layer, thereby forming a first spintronic element, wherein the magnetic layer, the MgO tunnel barrier, and the semiconducting layer are in proximity with each other, so that, upon application of a voltage across the device, the spin polarization of charge carriers flowing between the MgO tunnel barrier and the semiconducting layer is greater than 20%, wherein the MgO tunnel barrier and the semiconducting layer are lattice-matched each of the MgO tunnel barrier and the semiconducting layer being crystalline. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79)
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80. A device, comprising:
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a first layer that includes at least one magnetic material from the group consisting of ferromagnetic materials and ferrimagnetic materials; a MgO tunnel barrier in contact with the first layer; and a second layer that includes semiconductor material, the second layer being in contact with the MgO tunnel barrier, the MgO tunnel barrier being sandwiched between the first layer and the second layer, thereby forming a first spintronic element, wherein the first layer, the MgO tunnel barrier, and the second layer are configured to enable spin-polarized charge carrier transport between the semiconductor material and the magnetic material, wherein each of the MgO tunnel barrier and the semiconductor material is crystalline, and wherein; i) the amount of any oxide between the MgO tunnel barrier and the second layer and any oxide between the MgO tunnel barrier and the first layer is sufficiently low, and ii) the MgO tunnel barrier, the first layer, and the second layer are sufficiently free of defects, that the spin polarization of current flowing between the MgO tunnel barrier and the semiconductor material is greater than 40%. - View Dependent Claims (81, 82)
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83. A device, comprising:
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a first layer that includes at least one magnetic material from the group consisting of ferromagnetic materials and ferrimagnetic materials; a MgO tunnel barrier in contact with the first layer; and a second layer that includes semiconductor material, the second layer being in contact with the MgO tunnel barrier, the MgO tunnel barrier being sandwiched between the first layer and the second layer, thereby forming a first spintronic element, wherein the first layer, the MgO tunnel barrier, and the second layer are configured to enable spin-polarized charge carrier transport between the semiconductor material and the magnetic material, wherein each of the MgO tunnel barrier and the semiconductor material is crystalline, and wherein; i) the amount of any oxide between the MgO tunnel barrier and the second layer and any oxide between the MgO tunnel barrier and the first layer is sufficiently low, and ii) the MgO tunnel barrier the first layer, and the second layer are sufficiently free of defects, that the spin polarization of current flowing between the MgO tunnel barrier and the semiconductor material is greater than 20%.
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84. A method, comprising:
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forming a MgO tunnel barrier on a surface of an underlayer, wherein the surface is selected to be substantially free of oxide; and forming an overlayer on the MgO tunnel barrier to construct a spintronic element, with one of the underlayer and the overlayer including a layer of semiconductor material, and the other of the underlayer and the overlayer including a layer of magnetic material selected from the group consisting of ferromagnetic materials and ferrimagnetic materials, wherein the MgO tunnel barrier is sandwiched between the underlayer and the overlayer, said forming a MgO tunnel barrier including; depositing Mg onto the surface of the underlayer to form a Mg layer thereon; and directing additional Mg, in the presence of oxygen, towards the Mg layer to form a MgO tunnel barrier in contact with the underlayer, the oxygen reacting with the additional Mg and the Mg layer, wherein the thickness of the Mg layer is selected to be large enough to prevent oxidation of the underlayer but small enough that, upon reaction of the oxygen with the Mg layer, substantially all the Mg in the Mg layer is converted into MgO, and wherein the MgO tunnel barrier and the semiconductor material are formed so that they are lattice-matched, and each of the MgO tunnel barrier and the semiconductor material is crystalline. - View Dependent Claims (85, 86, 87)
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88. A method, comprising:
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forming a MgO tunnel barrier on a surface of an underlayer, wherein the surface is selected to be substantially free of oxide; and forming an overlayer on the MgO tunnel barrier to construct a spintronic element, with one of the underlayer and the overlayer including a layer of semiconductor material, and the other of the underlayer and the overlayer including a layer of magnetic material selected from the group consisting of ferromagnetic materials and ferrimagnetic materials, wherein the MgO tunnel barrier is sandwiched between the underlayer and the overlayer, and the MgO tunnel barrier is in direct contact with both the semiconductor material and the magnetic material. - View Dependent Claims (89, 90, 91, 92, 93, 94, 95)
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96. A device, comprising:
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a magnetic layer comprising at least one magnetic material from the group consisting of ferromagnetic materials and ferrimagnetic materials; a MgO tunnel barrier; and a semiconducting layer, wherein the MgO tunnel barrier is between the magnetic layer and the semiconducting layer, thereby forming a first spintronic element, wherein the magnetic layer, the MgO tunnel barrier, and the semiconducting layer are in proximity with each other and are configured so that, upon application of a voltage across the device, the spin polarization of charge carriers flowing between the MgO tunnel barrier and the semiconducting layer is greater than 20%, each of the MgO tunnel barrier and the semiconducting layer being crystalline. - View Dependent Claims (97, 98)
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Specification