Phase Separation and Transport Behavior in La0. 67-x Smx Sr0.33 MnO3 System

摘要

The magnetic behavior and the transport behavior of La_ 0.67-x Sm_ x Sr_ 0.33 MnO_ 3 (x=0.00, 0.10, 0.20, 0.30, 0.40, 0.50 and 0.60) systems were studied through measuring the M-T curves, electron spin resonance(ESR) curves and ρ-T curves. The samples exhibit a long-range ferromagnetic order when x=0.00, 0.10, a cluster-spin glass state when x=0.20 and 0.30, and an anti-ferromagnetic state at low temperatures when x=0.40, 0.50 and 0.60. The samples of x=0.30 and 0.40 show phase separation at temperatures above T_ c . The transport behavior of the sample of x=0.60 becomes abnormal when the doping is high, and an insulator-metal transition occurs near T_ c and then a metal-insulator transition occurs, which rarely appears in an ABO_ 3 structure. It is concluded that the magnetic and electric behavior changes of the systems depend on the extra magnetism and lattice distortion effect induced by Sm doping.