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Crystal Growth and Characterization of Magnetic Semiconductors Katsuaki Sato Department of Applied Physics Tokyo Univ. of A & T ISSGC11, July 27, 2001.

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Presentation on theme: "Crystal Growth and Characterization of Magnetic Semiconductors Katsuaki Sato Department of Applied Physics Tokyo Univ. of A & T ISSGC11, July 27, 2001."— Presentation transcript:

1 Crystal Growth and Characterization of Magnetic Semiconductors Katsuaki Sato Department of Applied Physics Tokyo Univ. of A & T ISSGC11, July 27, 2001

2 1. Introduction Spintronics:attracting attention because of its potential applicability to new functional devices combining transport and magnetic properties. Magnetic semiconductors: long history of research

3 History of Magnetic Semiconductors First generation: chromium chalcogenide spinels and europium chalcogenides Second generation: II-VI based diluted magnetic semiconductors (II-VI DMS)  optical devices Third generation: III-V based diluted magnetic semiconductors (III-V DMS)  electronic devices Fourth generation: room-temperature ferromagnetic semiconductors

4 2. First-generation Magnetic Semiconductors

5 Spinel chalcogenides Compou nds Magnetic order Band gap (eV) Transporting agent; Growth temperatures (  C) Lattice parameter (nm) ZnCr 2 S 4 AF, T N =13K Open tube Liquid transport CrCl 3 +ZnS 0.9974 CdCr 2 S 4 FM, T C =86K 1.8(0K) 1.57(RT) Open tube Cd+CrCl 3 +S 2 H+Cl, 1100→1030, Cl 2, 825→775; 825→775; 1000→750 CrCl 3, 950→900, 1000→950, 1000→750 1.0244 HgCr 2 S 4 Heli, T N =40K 0.98(0K) 1.42(RT) Cl 2, 900→850 1.0206 FeCr 2 S 4 Ferri, T C =177K Cl 2, H+Cl, 950→875 Open tube CrCl 3 on FeS HCl, 800→725 0.997

6 Spinel chalcogenides (cont’d) Compoun ds Magnetic order Band gap(eV) Transporting agent; Growth temperatures (  C) Lattice parameter (nm) MnCr 2 S 4 Ferri, T C =71K AlCl 3, 1000→9001.0045 CoCr 2 S 4 Ferri, T C =22 K NH 4 Cl, 1150→1000 H+Cl, 1030→940 Liq. transport CrCl 3 +CoS 1070→1020 0.990 CuCr 2 S 4 FM, T C =400K 0 HCl, 800→725 0.9629 ZnCr 2 Se 4 Spiral AF, T N =23K 1.1(0K) 1.29(RT) 1.0443 CdCr 2 Se 4 FM, T C =130K 1.15(0K) 1.32(RT) Cl 2, 825→780 CdCl 2, CdI 2 CrCl 3, 1000→750, 800→700, 800→750 1.0755 HgCr 2 Se 4 FM, T C =110K 0.32(0K) 0.84(RT) CrCl 3, 745→670, 700→670 AlCl 3, Al+Cl, 650→625 1.0753 CuCr 2 Se 4 FM, T C =426K 0AlCl 3 1.0357


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