magnetoresistance;
double perovskite;
manganite;
single crystals;
D O I:
10.1016/S0921-4526(98)00813-8
中图分类号:
O469 [凝聚态物理学];
学科分类号:
070205 ;
摘要:
We performed magnetisation (M) and transport measurements along the ab plane and the c direction in La2-2xSr1+2xMn2O7 single crystals for x = 0.4. In addition to a sharp para-ferromagnetic transition at T-c = 125 K, a weak maximum in M was found around 265 K. A sharp drop of resistivity at T-c associated with a semi-conductor to metal transition was found for both current orientations. The colossal magnetoresistance of the compound CMR = - (rho(H) - rho(0))/rho(0) was found to be similar to 100% in a held of 8 T near T-c. In contrast with the well-known La1-xSrxMnO3 type manganites, a CMR effect larger than 10% was present at all temperatures ranging between 5 and 300 K. (C) 1999 Elsevier Science B.V. All rights reserved.