Phenomenological Description of a Giant Temperature Hysteresis of the Ultrasound Velocity and the Internal Friction in Lanthanum Manganite

TL;DR

This paper explains the giant temperature hysteresis observed in ultrasound velocity and internal friction in lanthanum manganite using a phenomenological model involving two coexisting sublattices of oxygen octahedra in bistable potentials.

Contribution

It introduces a phenomenological model that accounts for the hysteresis by considering cooperative tilting-rotational oscillations of oxygen octahedra in bistable potentials.

Findings

The model successfully explains the observed hysteresis phenomena.

The cooperative tilting-rotational oscillations are key to the hysteresis.

The explanation aligns with experimental observations.

Abstract

We propose an explanation for the experimentally observed [JETP Lett. 74, 115 (2001)] giant temperature hysteresis of the ultrasound velocity and the internal friction in single crystals of lanthanum manganite (La0.8Sr0.2MnO3). The effect is interpreted within the framework of a phenomenological model based on the notion of two coexisting sublattices of the oxygen octahedra performing cooperative tilting-rotational oscillations in bistable potential fields.