机构地区:[1]Materials Research Laboratory, Suzhou College, Suzhou 234000, China [2]Structure Research Laboratory, University and Technology of China, Hefei 230026, China
出 处:《Journal of Rare Earths》2006年第2期206-213,共8页稀土学报(英文版)
基 金:ProjectsupportedbytheNationalNaturalScienceFoundationofChina(19934003);theStateKeyProjectofFundamentalResearchofChina(001CB610604)andNaturalScienceResearchProjectforInstitutionofHigherLearninginAnhuiProvince(2005KJ234)
摘 要: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, form from long-range ferromagnetic order to spin-cluster glass with the increase of Sm doping amount, the samples transstate 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 + AT^4.5, and the insulatorlike 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, p is resistivity, T is temperature, and A, ρ0, T0 are constants.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, form from long-range ferromagnetic order to spin-cluster glass with the increase of Sm doping amount, the samples transstate 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 + AT^4.5, and the insulatorlike 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, p is resistivity, T is temperature, and A, ρ0, T0 are constants.
关 键 词:giant magnetoresistant material magnetic structure transport behavior electron-magneton interaction variable-range hopping samarion doping rare earths
分 类 号:O482.54[一般工业技术—材料科学与工程]
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