High-field magnetotransport properties of La2/3Sr1/3MnO3 and Nd2/3Sr1/3MnO3 systems

摘要

The electrical resistivity (rho), magnetoresistance (MR), Hall coefficient (R-H) of La2/3Sr1/3MnO3 thin film, and MR of Nd2/3Sr1/3MnO3 polycrystalline samples have been studied over a wide temperature range and in high-magnetic fields up to 20 T. In the ferromagnetic (FM) phase, rho(T) follows an expression a(0)+a(2)T(2) +a(4)T(4) with and without applied field. This temperature dependence may be understood on the basis of scattering of charge carriers due to spin fluctuations. At low temperatures, magnetoconductivity of Nd2/3Sr1/3MnO3 increases linearly with H up to 20 T whereas for La2/3Sr1/3MnO3 deviation from linearity is observed in the high-field region. The Hall coefficient of La2/3Sr1/3MnO3 shows strong temperature dependence due to the skew scattering by the magnetic moments and exhibited the temperature dependence (T-2) principally due to that of the magnetization. The anomalous part of the Hall coefficient is zero at T=0, becomes negative with increasing temperature, and its magnitude is comparable with a normal component. The anomalous nature of the Hall resistivity is also reflected in the field dependence of R-H. The carrier density calculated from the normal Hall coefficient part is 3.5 x 10(21)/cc. [S0163-1829(98)08617-2]. [References: 30]