Large Low-Field Magnetoresistance Observed in Polycrystalline La0.7Ca0.3MnO3 Films
WANG Zhi-hai1, LIAN Gui-jun1, GAO Ju2, ZHOU Ya-qin1, KANG Jin-feng1, LI Mei-ya1,3, XIONG Guang-cheng1
1Department of Physics, Peking University, Beijing 100871
2Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong
3Department of Physics, Shantou University, Shantou 515063
Large Low-Field Magnetoresistance Observed in Polycrystalline La0.7Ca0.3MnO3 Films
WANG Zhi-hai1;LIAN Gui-jun1;GAO Ju2;ZHOU Ya-qin1;KANG Jin-feng1;LI Mei-ya1,3;XIONG Guang-cheng1
1Department of Physics, Peking University, Beijing 100871
2Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong
3Department of Physics, Shantou University, Shantou 515063
Abstract： Large low-field magnetoresistance (LFMR) of ∆p/pH = 40% is obtained at 163 K within ±3000 Oe in a polycrystalline La0.7Ca0.3MnO3 (LCMO) films prepared by pulsed laser deposition. The ratio ∆p/pH increases almost linearly with H in the measuring magnetic field range and the peak of LFMR ratios is observed near the resistivity peak temperature, which is different from the observation of spin-polarized intergrain tunnels. This experiment suggests that grain boundaries have large influences on the LFMR. The results indicate that a suitable film process can be used to increase the LFMR of LCMO films.
1999, Vol. 16 
