Abrupt field-induced transition triggered by magnetocaloric effect in phase-separated manganites

TL;DR

This paper investigates an ultrasharp, field-induced transition in phase-separated manganites at low temperatures, revealing a magnetocaloric effect that causes an abrupt temperature change and triggers an avalanche-like transition.

Contribution

It demonstrates the role of the magnetocaloric effect in abrupt phase transitions and introduces the concept of a critical growth rate leading to avalanche effects in manganites.

Findings

Magnetization and heat show step-like transitions below 5 K.

An abrupt temperature increase occurs at a critical magnetic field.

A critical ferromagnetic growth rate triggers an avalanche effect.

Abstract

The occurrence at low temperatures of an ultrasharp field-induced transition in phase separated manganites is analyzed. Experimental results show that magnetization and specific heat step-like transitions below 5 K are correlated with an abrupt change of the sample temperature, which happens at a certain critical field. This temperature rise, a magnetocaloric effect, is interpreted as produced by the released energy at the transition point, and is the key to understand the existence of the abrupt field-induced transition. A qualitative analysis of the results suggests the existence of a critical growing rate of the ferromagnetic phase, beyond which an avalanche effect is triggered.