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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.
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 MT 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 = 0.50 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 that that magnetic and electric behavior changes of the systems depend on the extra magnetism and lattice distortion effect induced by Sm doping.