Band structures, magnetic properties, and enhanced magnetoresistance in the high pressure phase of Gd and Y doped two-dimensional perovskite Sr2CoO4 compounds

Authors

Xiaolin Wang, University of WollongongFollow
E Takayama-Muromachi, National Institute for Materials, Japan
S X. Dou, University of WollongongFollow
Zhenxiang Cheng, University of WollongongFollow

RIS ID

20074

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.

Abstract

The authors present their studies on the band structures and on the magnetic and magnetotransport properties of the high pressure phase of Sr_2-xRE_xCoO₄ [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.