Photoluminescence and Magnetism in the New Magnetic Semiconductors: K2Cd3(1-x)Mn3xS
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- 作者：Enos A. Axtell ; III ; Jason Hanko ; Jerry A. Cowen ; and Mercouri G. Kanatzidis
- 刊名：Chemistry of Materials
- 出版年：2001
- 出版时间：September 2001
- 年：2001
- 卷：13
- 期：9
- 页码：2850 - 2863
- 全文大小：311K
- 年卷期：v.13,no.9(September 2001)
- ISSN：1520-5002
文摘
A new family of magnetic semiconductors, K2Cd3(1-x)Mn3xS4, prepared from molten K2Sxis reported. For x 
0.6, the compounds crystallize in the K2Cd3S4 structure type. The cellvolumes of the series obey Vegard's Law for solid solutions. The compounds range in colorfrom yellow through orange brown to red and possess platelike morphologies. A structuraltransformation occurs between x = 0.7 and x = 0.9. Red plates of K2Cd0.4Mn2.6S4 (x = 0.87)crystallize in the space group Ccca with a = 5.9217(8) Å, b = 13.531(1) Å, c = 11.0696(8) Å,and V = 887.0(1) Å3. The end member, K2Mn3S4, crystallizes in the space group Ccca witha = 11.0637(7) Å, b = 26.830(2) Å c = 5.8180(4) Å, and V = 1727 Å3. For x 0.6, thecompounds form as (M3S4)n2n- layers, interspersed by K+ cations. These layers are composedonly of M3S42- units shaped like truncated cubes. When x = 0.87, a new structure related tothat of Cs2Mn3S4 is observed. The end member of the series (i.e., x = 1) K2Mn3S4 is revealedto have a related yet surprising structure. The compounds display room-temperature bandgaps ranging from 2.79 to 2.92 eV. Absorptions in the mid-gap region, due to Mn2+-basedd-d transitions, are also observed. The compounds are strongly emissive in the visiblespectrum at room temperature, with the light emission shifted to the red immediately uponthe introduction of small amounts of manganese. The magnetic properties of these compoundsevolve from classical paramagnetic to spin glass as a function of x. For x 
0.05, thecompounds deviate from Curie-Weiss behavior. Antiferromagnetic coupling is observed inall cases. With very high Mn content transitions to magnetically complex phases are observedwith possible spin-glass-like behavior.
0.6, the compounds crystallize in the K2Cd3S4 structure type. The cellvolumes of the series obey Vegard's Law for solid solutions. The compounds range in colorfrom yellow through orange brown to red and possess platelike morphologies. A structuraltransformation occurs between x = 0.7 and x = 0.9. Red plates of K2Cd0.4Mn2.6S4 (x = 0.87)crystallize in the space group Ccca with a = 5.9217(8) Å, b = 13.531(1) Å, c = 11.0696(8) Å,and V = 887.0(1) Å3. The end member, K2Mn3S4, crystallizes in the space group Ccca witha = 11.0637(7) Å, b = 26.830(2) Å c = 5.8180(4) Å, and V = 1727 Å3. For x 0.6, thecompounds form as (M3S4)n2n- layers, interspersed by K+ cations. These layers are composedonly of M3S42- units shaped like truncated cubes. When x = 0.87, a new structure related tothat of Cs2Mn3S4 is observed. The end member of the series (i.e., x = 1) K2Mn3S4 is revealedto have a related yet surprising structure. The compounds display room-temperature bandgaps ranging from 2.79 to 2.92 eV. Absorptions in the mid-gap region, due to Mn2+-basedd-d transitions, are also observed. The compounds are strongly emissive in the visiblespectrum at room temperature, with the light emission shifted to the red immediately uponthe introduction of small amounts of manganese. The magnetic properties of these compoundsevolve from classical paramagnetic to spin glass as a function of x. For x 0.05, thecompounds deviate from Curie-Weiss behavior. Antiferromagnetic coupling is observed inall cases. With very high Mn content transitions to magnetically complex phases are observedwith possible spin-glass-like behavior.