The Dielectric Response of La0.5Ca0.5-xSrxMnO3 (0.1 <= x <= 0.4) Manganites with Different Magnetic Ground States

TL;DR

This study investigates how the dielectric properties of La0.5Ca0.5-xSrxMnO3 manganites vary with temperature and magnetic states, revealing correlations between dielectric behavior and magnetic phase transitions.

Contribution

It provides new insights into the dielectric response of doped manganites with different magnetic ground states and their relation to magnetic transitions.

Findings

Maximum dielectric permittivity near magnetic transition temperatures.

Activation energies around 0.12 eV for certain compositions.

Strong temperature dependence of permittivity near magnetic phase transitions for x=0.4.

Abstract

The dielectric behavior of half doped manganites La0.5Ca0.5-xSrxMnO3 (0.1 \leq \times \leq 0.4) with varying magnetic ground states has been studied. The real part of relative permittivity as a function of temperature {\epsilon}^'(T), exhibits a maximum around the ferromagnetic (TC) and charge ordering transition (TCO) temperatures accompanied with high dielectric losses. The activation energies obtained for x = 0.1 and 0.3 samples below TCO are the same ~ 0.12eV, whereas the relaxation time constant varies in the range 2.8 \times 10-9 s - 6.03 \times 10-11 s. In contrast to samples having x \leq 0.3, for x = 0.4 doping the dielectric permittivity exhibits a strong temperature dependence in the vicinity of magnetic phase transitions. This behavior may be correlated with the presence of competing magnetic interactions (magnetic polarons) close to the magnetic transitions.