Electron paramagnetic resonance investigation of the electron-doped manganite La1−xTexMnO3 (0.1 ≤ x ≤0.2)

Abstract

The electron paramagnetic resonance (EPR) properties of the electron-doped manganite La_1−xTe_xMnO₃ (0.1 ≤ x ≤ 0.2) are investigated based on the data of EPR spectra, resistivity, and magnetic susceptibility. With decreasing temperature from 400 K, the EPR linewidth ΔH_PP decreases and passes through a minimum at T_min, then substantially increases with further decreasing temperature. The broadening of the EPR linewidth above T_min can be understood in terms of the increase in the relaxation rate of spin of e_g polarons to the lattice with increasing temperature due to the similarity between the temperature dependence of the linewidth ΔH_pp(T) and the conductivity σ(T). For the samples with x = 0.1 and 0.15, the conductivity activation energy E_σ is comparable with the activation energy E_a deduced from the linewidth. Whereas for the x = 0.2 sample, there is a large difference between E_σ (0.2206 eV) and E_a (0.0874 eV).