The magnetic properties and magnetoresistance of Pr_(0.7)Pb_(0.3)MnO_(3) single crystals have been studied.At low temperature,the temperature dependence of magnetization can be represented as M(T)=M(0)(1-BT^(3/2)).A l...The magnetic properties and magnetoresistance of Pr_(0.7)Pb_(0.3)MnO_(3) single crystals have been studied.At low temperature,the temperature dependence of magnetization can be represented as M(T)=M(0)(1-BT^(3/2)).A large B value was observed.The spontaneous magnetic moment is slightly larger than the spin-only value for Mn3+and Mn4+ions.Above the Curie temperature,the susceptibility obeys the Curie-Weiss Law and the resistivity R can fit well with R0 exp(T0/T)^(1/4).It is found that the effective paramagnetic moment obtained from the Curie constant is larger than the theoretical value.The large effective paramagnetic moment may originate from the magnetic clusters.A large low-field magnetoresistance of ΔR/R(0)=-50% is observed at 230 K in 1T.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.19774032.
文摘The magnetic properties and magnetoresistance of Pr_(0.7)Pb_(0.3)MnO_(3) single crystals have been studied.At low temperature,the temperature dependence of magnetization can be represented as M(T)=M(0)(1-BT^(3/2)).A large B value was observed.The spontaneous magnetic moment is slightly larger than the spin-only value for Mn3+and Mn4+ions.Above the Curie temperature,the susceptibility obeys the Curie-Weiss Law and the resistivity R can fit well with R0 exp(T0/T)^(1/4).It is found that the effective paramagnetic moment obtained from the Curie constant is larger than the theoretical value.The large effective paramagnetic moment may originate from the magnetic clusters.A large low-field magnetoresistance of ΔR/R(0)=-50% is observed at 230 K in 1T.
