US5538800A
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Magnetoresistive oxide material and articles comprising the material
Assignee: AT&T Inc
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Filing: 1994-09-29
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Granted: 1996-07-23
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Expires: 2014-09-29
Abstract
Abstract Materials of composition La v X w M y Mn z O x , with x selected from Mg, Sc, Al, Zn, Cd, In and the rare earths that have an ionic radius smaller than that of La, with M selected from Ca, Sr, Ba and Pb, and with v, w, y, z and x in the ranges 0.45-0.85, 0.01-0.20, 0.20-0.45, 0.7-1.3 and 2.5-3.5, respectively, can have substantially improved magnetoresistance (MR) ratios, as compared to the corresponding X-free comparison material. In particular, the novel materials in polycrystalline (or non-epitaxial thin film) form can have relatively large MR ratios. For instance, polycrystalline La 0 .60 Y 0 .07 Ca 0 .33 MnO x had a peak MR ratio in excess of 10,000% (in absolute value) in a field of 6 T.
Inventors
- 👤 Sungho Jin
- 👤 Mark T. McCormack
- 👤 Henry M. O'Bryan, Jr.
- 👤 Warren W. Rhodes
- 👤 Thomas H. Tiefel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:18
CPC Classifications
H; H10; H10N; H10N50/00; H10N50/80; H10N50/85; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/11; Y10T428/1107
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
106 words
An article comprising a quantity of magnetoresistive material that comprises La, Mn and oxygen, CHARACTERIZED IN THAT the material has nominal composition La v X w M y Mn z O x , where X is selected from the group consisting of Mg, Sc, Al, Zn, Cd, In and the rare earths that have an ionic radius smaller than that of La, M is selected from the group consisting of Ca, Sr, Ba and Pb, v is in the range 0.45-0.85, w is in the range 0.01-0.20, y is in the range 0.2-0.45, z is in the range 0.7-1.3, and x is in the range 2.5-3.5.
Claim 2
Dependent Claim
106 words
An article comprising a quantity of magnetoresistive material that comprises La, Mn and oxygen, CHARACTERIZED IN THAT the material has nominal composition La v X w M y Mn z O x , where X is selected from the group consisting of Mg, Sc, Al, Zn, Cd, In and the rare earths that have an ionic radius smaller than that of La, M is selected from the group consisting of Ca, Sr, Ba and Pb, v is in the range 0.45-0.85, w is in the range 0.01-0.20, y is in the range 0.2-0.45, z is in the range 0.7-1.3, and x is in the range 2.5-3.5.
Claim 3
Dependent Claim
26 words
An article according to claim 1, wherein X is selected from the group consisting of Mg, Sc, Al, Zn, Cd, Y, Pr, Nd, Sm and Gd.
Claim 4
Dependent Claim
10 words
An article according to claim 2, wherein X is Y.
Claim 5
Dependent Claim
24 words
An article according to claim 1, wherein v, w, y, z and x are in the ranges 0.55-0.75, 0.02-0.15, 0.25-0.40, 0.7-1.3 and 2.5-3.5, respectively.
Claim 6
Dependent Claim
32 words
An article according to claim 1, wherein said quantity of magnetoresistive material comprises polycrystalline material, or said quantity comprises a thin film of the material that is not epitaxial with a substrate.
Claim 7
Dependent Claim
106 words
An article comprising a quantity of magnetoresistive material that comprises La, Mn, M and O, where M is selected from the group consisting of Ca, Sr, Ba and Pb; CHARACTERIZED IN THAT i) the quantity of material comprises polycrystalline material or a thin film that is not epitaxial with a substrate; and ii) the quantity of material has a peak magnetoresistance ratio at 6 Tesla of more than 2000% in absolute value, wherein the material also comprises X, where X is selected from the group consisting of Mg, Sc, Al, Zn, Cd and the rare earths that have an ionic radius smaller than that of La.
Claim 8
Dependent Claim
106 words
An article comprising a quantity of magnetoresistive material that comprises La, Mn, M and O, where M is selected from the group consisting of Ca, Sr, Ba and Pb; CHARACTERIZED IN THAT i) the quantity of material comprises polycrystalline material or a thin film that is not epitaxial with a substrate; and ii) the quantity of material has a peak magnetoresistance ratio at 6 Tesla of more than 2000% in absolute value, wherein the material also comprises X, where X is selected from the group consisting of Mg, Sc, Al, Zn, Cd and the rare earths that have an ionic radius smaller than that of La.
Claim 9
Dependent Claim
114 words
An article comprising a quantity of magnetoresistive material that comprises La, Mn, M and O, where M is selected from the group consisting of Ca, Sr, Mn and Pb; CHARACTERIZED IN THAT the quantity of material comprises one or more further elements X selected to provide the quantity of material with a peak magnetoresistance ratio in a field of 6 T that is at least twice as large in absolute value as the peak magnetoresistance ratio of an X-free comparison material in a field of 6 T, where X is selected from the group consisting of Mg, Sc, Al, Zn, Cd and the rare earths that have ionic radius smaller than that of La.
Claim 10
Dependent Claim
114 words
An article comprising a quantity of magnetoresistive material that comprises La, Mn, M and O, where M is selected from the group consisting of Ca, Sr, Mn and Pb; CHARACTERIZED IN THAT the quantity of material comprises one or more further elements X selected to provide the quantity of material with a peak magnetoresistance ratio in a field of 6 T that is at least twice as large in absolute value as the peak magnetoresistance ratio of an X-free comparison material in a field of 6 T, where X is selected from the group consisting of Mg, Sc, Al, Zn, Cd and the rare earths that have ionic radius smaller than that of La.
Claim 11
Dependent Claim
118 words
An article comprising a quantity of magnetoresistive material that comprises La, Mn, M and O, where M is selected from the group consisting of Ca, Sr, Ba and Pb; CHARACTERIZED IN THAT the quantity of material comprises one or more further elements X selected to provide the quantity of material with a lattice constant that is at least 0.05% smaller than the lattice constant of an X-free comparison material, whereby the quantity of material has an improved magnetoresistance ratio as compared to said X-free comparison material, wherein X is one or more elements selected from the group consisting of Mg, Sc, Al, Zn, Cd and the rare earths that have an ionic radius smaller than that of La.
Claim 12
Dependent Claim
118 words
An article comprising a quantity of magnetoresistive material that comprises La, Mn, M and O, where M is selected from the group consisting of Ca, Sr, Ba and Pb; CHARACTERIZED IN THAT the quantity of material comprises one or more further elements X selected to provide the quantity of material with a lattice constant that is at least 0.05% smaller than the lattice constant of an X-free comparison material, whereby the quantity of material has an improved magnetoresistance ratio as compared to said X-free comparison material, wherein X is one or more elements selected from the group consisting of Mg, Sc, Al, Zn, Cd and the rare earths that have an ionic radius smaller than that of La.
References Cited (Backward Citations)
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