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
The influence of Cr addition on the magnetic moment,Curie temperature and crystallization temperature of amorphous Nd_(4)Fe_(77.5)B_(18.5) alloy was investigated.With increasing Cr content,the magnetization and Curie ...The influence of Cr addition on the magnetic moment,Curie temperature and crystallization temperature of amorphous Nd_(4)Fe_(77.5)B_(18.5) alloy was investigated.With increasing Cr content,the magnetization and Curie temperature decrease,but the crystallization temperature increases.It is found that the substitution of Cr for Fe can enhance greatly the coercivity of crystallized sample.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.
基金Supported by the State Key Laboratory of Magnetism,Institute of Physics,Chinese Academy of Sciences.
文摘The influence of Cr addition on the magnetic moment,Curie temperature and crystallization temperature of amorphous Nd_(4)Fe_(77.5)B_(18.5) alloy was investigated.With increasing Cr content,the magnetization and Curie temperature decrease,but the crystallization temperature increases.It is found that the substitution of Cr for Fe can enhance greatly the coercivity of crystallized sample.
