Magnetic contributions to the low-temperature specific heat of the ferromagnetic insulator: Pr0.8Ca0.2MnO3

TL;DR

This study investigates the low-temperature magnetic excitations in Pr0.8Ca0.2MnO3, revealing that specific heat behavior is influenced by both ferromagnetic spin waves and Schottky-like contributions from Pr3+ ions.

Contribution

It provides new insights into the magnetic excitations in ferromagnetic insulators, highlighting the role of Pr3+ ions and their Zeeman splitting in specific heat behavior.

Findings

Specific heat decreases under magnetic field, indicating suppression of spin waves.

Poor qualitative agreement with pure ferromagnetic spin wave model at low temperature.

Schottky-like contribution from Pr3+ ions affects the specific heat.

Abstract

The Pr(1-x}CaxMnO3 system exhibits a ferromagnetic insulating state for the composition range x<0.25. A metallic ferromagnetic state is never realized because of the low hole concentration and the very small averaged A-site cation radius. In the present study, the nature of the magnetic excitations at low temperature has been investigated by specific heat measurements on a Pr0.8Ca0.2MnO3 single crystal. The decrease of the specific heat under magnetic field is qualitatively consistent with a suppression of ferromagnetic spin waves in a magnetic field. However, at low temperature, the qualitative agreement with the ferromagnetic spin waves picture is poor. It appears that the large reduction of the specific heat due to the spin waves is compensated by a Schottky-like contribution possibly arising from a Zeeman splitting of the ground state multiplet of the Pr{3+} ions.