The magnetotransport properties of LaMn1-xCrxO3 manganites

The Cr-doping effects on the structure, magnetotransport properties of LaMn 1-xCrxO3 manganites were studied. Our results showed that Cr-doping on the Mn-site enhances the ferromagnetic interaction of LaMn1-xCrxO3 manganites. On increasing the x value, the paramagnetic to ferromagnetic transition tem perature, T-m, first increased, reached a maximum (220 K), then decreased. Accompanied with the magnetic transition for the samples of 0.05 less than or equal to x less than or equal to 0.2, a resistivity shoulder appeared on their rho(T) curve, and for x = 0.05, a metal-insulator transition was als o induced. In the range of 0.05 less than or equal to x less than or equal to 0.3, an MR peak can be seen on each MR(T) curve. The Cr-doping effects m ay be ascribed to the similar t(2g)(3) electronic configurations of Cr3+ an d Mn4+, which allows a double-exchange interaction between the Cr3+ and Mn4 + ions. (C) 2000 Elsevier Science B.V. All rights reserved.