Magnetoresistive element
First Claim
1. A magnetoresistive element comprising a substrate and a multi-layer film formed on the substrate, the multi-layer film comprising a tunnel layer and a pair of magnetic layers that sandwich the tunnel layer, wherein a resistance value changes with a relative angle formed by magnetization directions of the pair of magnetic layers, wherein a conductive layer is arranged between the substrate and the tunnel layer, and wherein the conductive layer is at least one selected from:
- a) a conductor composed of at least one selected from Pt, Pd, Ag, Au, C, Si, Ge, Sn and Pb;
b) an amorphous film;
c) a microcrystalline film having an average crystal diameter of 5 nm or less; and
d) a laminate including a Cu film and a non-Cu metal film.
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Accused Products
Abstract
The present invention provides a tunnel magnetoresistive (TMR) element that increases a MR ratio and suppresses the unevenness in resistance. In an embodiment of the present invention, a surface property-controlling layer is arranged between the substrate and the tunnel layer. In another embodiment, at least one of the magnetic layers sandwiching the tunnel layer has an oriented crystal plane other than the closest packed plane. In still another embodiment, the at least one of the magnetic layers includes a magnetic element and a non-magnetic element and has an average electron number of 23.5 to 25.5 or 26.5 to 36. In still another embodiment, the TMR element includes an excess-element capturing layer. This layer includes an alloy or a compound that contains the excess element. The content of the excess element in the capturing layer is higher than those in the magnetic layers.
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Citations
21 Claims
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1. A magnetoresistive element comprising a substrate and a multi-layer film formed on the substrate, the multi-layer film comprising a tunnel layer and a pair of magnetic layers that sandwich the tunnel layer,
wherein a resistance value changes with a relative angle formed by magnetization directions of the pair of magnetic layers, wherein a conductive layer is arranged between the substrate and the tunnel layer, and wherein the conductive layer is at least one selected from: -
a) a conductor composed of at least one selected from Pt, Pd, Ag, Au, C, Si, Ge, Sn and Pb;
b) an amorphous film;
c) a microcrystalline film having an average crystal diameter of 5 nm or less; and
d) a laminate including a Cu film and a non-Cu metal film. - View Dependent Claims (2, 3, 4, 5)
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6. A magnetoresistive element comprising a substrate and a multi-layer film formed on the substrate, the multi-layer film comprising a tunnel layer and a pair of magnetic layers that sandwich the tunnel layer,
wherein a resistance value changes with a relative angle formed by magnetization directions of the pair of magnetic layers, wherein at least one layer selected from the pair of magnetic layers comprises at least one selected from: -
e) a lattice strain expressed by a lattice constant difference in a range of 0.1% to 5% with respect to a lattice constant that is calculated from the crystal structure of said at least one layer;
f) a crystal structure that is different from a preferential crystal structure at the ordinary temperature and the atmospheric pressure; and
g) a polycrystalline structure having an oriented crystal plane controlled to be other than the closest packed plane of the crystal structure of said at least one layer. - View Dependent Claims (7, 8, 9, 10)
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11. A magnetoresistive element comprising a substrate and a multi-layer film formed on the substrate, the multi-layer film comprising a tunnel layer and a pair of magnetic layers that sandwich the tunnel layer,
wherein a resistance value changes with a relative angle formed by magnetization directions of the pair of magnetic layers, wherein at least one layer selected from the pair of magnetic layers comprises at least one element selected from Fe, Co and Ni, and an element other than Fe, Co and Ni, and wherein an average electron number of said at least one layer is in a range of 23.5 to 25.5 or 26.5 to 36, where the average electron number is a per-atom electron number calculated on the basis of the composition ratio of said at least one layer.
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15. A magnetoresistive element comprising a substrate and a multi-layer film formed on the substrate, the multi-layer film comprising a tunnel layer and a pair of magnetic layers that sandwich the tunnel layer,
wherein a resistance value changes with a relative angle formed by magnetization directions of the pair of magnetic layers, wherein at least one layer selected from the layers in the multi-layer film that is other than the pair of magnetic layers comprises an excess element, and the excess element decreases spin polarization in at least one magnetic layer selected from the magnetic layers when the concentration of the excess element in said at least one magnetic layer increases, and wherein the multi-layer film further comprises an excess-element capturing layer including an alloy or a compound that contains the excess element, and the content of the excess element in the excess-element capturing layer is higher than those in the magnetic layers.
Specification