Publication Details

Wang, X, Takayama-Muromachi, E, Dou, SX & Cheng, Z (2007), Band structures, magnetic properties, and enhanced magnetoresistance in the high pressure phase of Gd and Y doped two-dimensional perovskite Sr2CoO4 compounds, Applied Physics Letters, 91(6), pp. 062501-1-062501-3.


The authors present their studies on the band structures and on the magnetic and magnetotransport properties of the high pressure phase of Sr2-xRExCoO4 [rare earth (RE)=Gd and Y, x=0.1-0.5] compounds which were synthesized by a high pressure and high temperature technique. The authors found that as x increases, the magnetoresistance {(PH-P0)/p0} increases up to -17% at 5 K and 7 T, which is 2.5 times higher than that for undoped Sr2CoO4, although the ferromagnetic transition drops from 255 to 200 K for the Gd doping with x=0.3. The saturation moments at low temperature are significantly enhanced for the Gd doped Sr2CoO4. Observation of a close correlation between resistance and field revealed a strong spin-dependent tunneling magnetoresistance. First-principles band structure calculations indicate that high spin polarization is present for both undoped and doped compounds.



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