Transport Property of La0.67-xSmxSr0.33MnO3 at Heavy Samarium Doping (0.40≤x≤0.60)
来源期刊：JOURNAL OF RARE EARTHS2006年第2期
论文作者：Yan Guoqing Guo Huanyin Tong Wei Liu Ning
Key words：giant magnetoresistant material; magnetic structure; transport behavior; electron-magneton interaction; variable-range hopping; samarion doping; rare earths;
Abstract: The influence of heavy samarion (Sm) doping(0.40≤x≤0.60) on magnetic and electric properties of La0.67-xSmxSr0.33MnO3 was investigated by measuring the magnetization-temperature (M～T) curves, magnetization-magnetic density (M～H) curves, resistivity-temperature(ρ-T) curves and magnetoresistivity-temperature(MR～T) curves of the samples under different temperatures.It is found that, with the increase of Sm doping amount, the samples transform from long-range ferromagnetic order to spin-cluster glass state and anti-ferromagnetic state;and when x=0.60, the transport property becomes abnormal under magnetic background;and the magnetic structure changes and extra magnetic coupling induced by doping leads to colossal magnetoresistance effect.The transport mechanism of metallic conduction at low temperature is mainly electron-magneton interaction and can be fitted by the formula ρ=ρ0+AT4.5, and the insulator-like transport mechanism on high temperature range is mainly the function of variable-range hopping and can be fitted by the formula ρ=ρ0exp(T0/T)1/4.In the formulas above, ρ is resistivity, T is temperature, and A, ρ0, T0 are constants.
Yan Guoqing1，Guo Huanyin1，Tong Wei2，Liu Ning1
(1.Materials Research Laboratory, Suzhou College, Suzhou 234000, China;
2.Structure Research Laboratory, University and Technology of China, Hefei 230026, China)
Abstract:The influence of heavy samarion (Sm) doping(0.40≤x≤0.60) on magnetic and electric properties of La0.67-xSmxSr0.33MnO3 was investigated by measuring the magnetization-temperature (M～T) curves, magnetization-magnetic density (M～H) curves, resistivity-temperature(ρ-T) curves and magnetoresistivity-temperature(MR～T) curves of the samples under different temperatures.It is found that, with the increase of Sm doping amount, the samples transform from long-range ferromagnetic order to spin-cluster glass state and anti-ferromagnetic state;and when x=0.60, the transport property becomes abnormal under magnetic background;and the magnetic structure changes and extra magnetic coupling induced by doping leads to colossal magnetoresistance effect.The transport mechanism of metallic conduction at low temperature is mainly electron-magneton interaction and can be fitted by the formula ρ=ρ0+AT4.5, and the insulator-like transport mechanism on high temperature range is mainly the function of variable-range hopping and can be fitted by the formula ρ=ρ0exp(T0/T)1/4.In the formulas above, ρ is resistivity, T is temperature, and A, ρ0, T0 are constants.
Key words:giant magnetoresistant material; magnetic structure; transport behavior; electron-magneton interaction; variable-range hopping; samarion doping; rare earths;
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