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Magnetic semiconductor material

外国特許コード F110003550
整理番号 BE06003WO
掲載日 2011年6月29日
出願国 アメリカ合衆国
出願番号 90902006
公報番号 20090042058
公報番号 8420236
出願日 平成18年3月17日(2006.3.17)
公報発行日 平成21年2月12日(2009.2.12)
公報発行日 平成25年4月16日(2013.4.16)
国際出願番号 JP2006305405
国際公開番号 WO2006098432
国際出願日 平成18年3月17日(2006.3.17)
国際公開日 平成18年9月21日(2006.9.21)
優先権データ
  • 特願2005-080572 (2005.3.18) JP
  • 特願2005-378897 (2005.12.28) JP
  • 2006JP305405 (2006.3.17) WO
発明の名称 (英語) Magnetic semiconductor material
発明の概要(英語) A magnetic semiconductor material contains at least one type of transition metals (Mn2+, Fe3+, Ru3+, Re2+, and Os3+) having five electrons in the d atomic orbital as a magnetic ion, in which the magnetic semiconductor material exhibits n-type electrical conduction by injection of an electron carrier and p-type electric conduction by injection of a hole carrier.
A specific example is a layered oxy-pnictide compound represented by LnMnOPn (wherein Ln is at least one type selected from Y and rare earth elements of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and Pn is at least one selected from pnicogen elements of N, P, As, Bi, and Sb).
A high-sensitivity magnetic sensor, current sensor, or memory device can be made by using a magnetic pn homojunction structure made of thin films composed of the magnetic semiconductor material.
従来技術、競合技術の概要(英語) BACKGROUND ART
A magnetic semiconductor compound is a unique compound having both semiconducting electrical property and magnetic property.
Because the magnetic semiconductor compound exhibits a large magnetoresistive effect near the magnetic transition temperature (Curie temperature Tc or Neel temperature TN), its application to magnetic sensors and the like are expected.
However, most magnetic semiconductor compounds discovered so far exhibit only one conductivity type, i.e., either n-type or p-type, and no magnetic semiconductor compound that can exhibit both conductivity types, i.e., n-type and p-type, has been discovered to date except for CdCr2Se4 (non-patent document 1).
In CdCr2Se4, the 3d6 electron of a Cr3+ ion is accountable for magnetic property and 4p of Se and the 4s electron of Cd are the hole and the electron accountable for the conduction.
Thus, there is little interaction between the magnetic property and the electrical conduction.
Furthermore, Cr3+ having a 3d6 electron configuration disadvantageously exhibits a magnetic moment smaller than and a Curie temperature (150 K) lower than those of the 3d5 electron configuration of the Mn2+ ion and the Fe3+ ion.
Due to these drawbacks, a pn homojunction magnetic device suitable for practical use has not been available.
Another approach of making various magnetic devices is by using a pn junction structure of a magnetic semiconductor and a nonmagnetic semiconductor (nonpatent documents 2 to 4).
These devices are named spin bipolar devices but are not put to practical use because formation of high-quality pn junction structures is difficult and the magnetic transition temperature of the magnetic semiconductor is lower than room temperature.
Nonpatent document 1: P. W. Cheng et al.
IEEE, Trans.
Magn. 4, 702-704 (1968)
Nonpatent document 2: M. Johnsonn et al.
Phys. Rev. Lett. 55, 1790 (1985)
Nonpatent document 3: Fiederling et al.
Nature 402, 787 (1999)
Nonpatent document 4: Ohno et al.
Nature 402, 790 (1999)

特許請求の範囲(英語) [claim1]
1. A pn homojunction structure of magnetic material, comprising: an n-type conductive magnetic semiconductor material represented by LnMnO1-x1Pn1-y1,
wherein x1 and y1 satisfy relations: 0<x1<0.1 and 0<y1<0.1, and
a p-type conductive magnetic semiconductor material adjoining the n-type conductive magnetic semiconductor material, the p-type conductive magnetic semiconductor material being represented by LnMnO1+x2Pn1+y2,
wherein x2 and y2 satisfy 0<x2<0.1 and 0<y2<0.1,
wherein LnMnOPn is a layered oxy-pnictide compound,
Ln is at least one type selected from Y and rare earth elements of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dv, Ho, Er, Tm, Yb, and Lu, and
Pn is at least one selected from pnicogen elements of N, P, As, Bi, and Sb.
[claim2]
2. The pn homojunction structure of magnetic material according to claim 1, wherein the magnetic semiconductor material is included in a magnetic pn homojunction device.
[claim3]
3. The pn homojunction structure of magnetic material according to claim 2, wherein the magnetic pn homojunction device is one device selected from a device for detecting an external magnetic field, a device for detecting electrical current, and a memory device having functions of reading, writing, and retaining information.
[claim4]
4. A pn homojunction structure of magnetic material, comprising: a p-type conductive magnetic semiconductor material represented by LnMnOPn Ln3+ ion site is doped with a divalent metal ion selected from Mg2+, Ca2+, Sr2+, and Ba2+, and
an n-type conductive magnetic semiconductor material adjoining the p-type conductive magnetic semiconductor material, the n-type conductive magnetic semiconductor material being represented by LnMnOPn, wherein Ln3+ ion site is doped with a tetravalent metal ion selected from Ti4+, Zr4+, Hf4+, Si4+, Ge4+, Sn4+, and Pb4+,
wherein LnMnOPn is a layered oxy-pnictide compound,
Ln is at least one type selected from Y and rare earth elements of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and
Pn is at least one selected from pnicogen elements of N, P, As, Bi, and Sb.
[claim5]
5. The pn homojunction structure of magnetic material according to claim 4, wherein the magnetic semiconductor material is included in a magnetic pn homojunction device.
  • 発明者/出願人(英語)
  • HOSONO HIDEO
  • HIRANO MASAHIRO
  • HIRAMATSU HIDENORI
  • KAMIYA TOSHIO
  • YANAGI HIROSHI
  • MOTOMITSU EIJI
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
国際特許分類(IPC)
米国特許分類/主・副
  • 428/693.1
  • 257/421
  • 257/E21.665
  • 257/E31.057
参考情報 (研究プロジェクト等) ERATO/SORST Exploring and developing applications for active functions utilizing nanostructure embedded in transparent oxides AREA
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