Magnetic and Electric properties of La_{1-delta}MnO_{3}

TL;DR

This study explores the magnetic and electric properties of La_{1-delta}MnO_{3} powders, revealing complex magnetic phases, the presence of magnetoelastic polarons, and their effects on magnetic behavior across temperature ranges.

Contribution

It provides new insights into the magnetic phase diagram and polaron behavior in La_{1-delta}MnO_{3} with varying delta, highlighting the coexistence of ferromagnetism and insulating states.

Findings

La_{0.97}MnO_{3} has a canted magnetic structure at low temperature.

Above T_C, it exhibits a paramagnetic state with large magnetic moments due to polarons.

Polarons persist at high temperatures even with increased delta, influencing magnetic properties.

Abstract

The magnetic phase diagram of $La_{1-\delta}MnO_{3}$ powdered samples have been studied as a function of $\delta $ in the low doping range. $La_{0.97}MnO_{3}$ has a canted magnetic structure at low temperature $(\theta \simeq 130\QTR{group}{{}^{\circ}})$. Above $T_{C}=118K$, it becomes a paramagnet with a huge effective magnetic moment, $\mu_{eff}=6.0\mu_{B}$, reflecting the presence of magnetoelastic polarons which are not affected by the magnetic field (up to 20T) nor the temperature $(1.2T_{C}<T<2.5T_{C})$. When $\delta $ is increased to $\delta =0.07$, polarons are still presen at high temperature, with a smaller size: $\mu_{eff}=5.8\mu_{B}$. The system becomes fully ferromagnetic below 170K but remains insulating down to the lowest temperature.