Avalanche-like metamagnetic transition in (LaNd)CaMnO manganites

TL;DR

This paper studies ultrasharp, avalanche-like metamagnetic transitions in LaNdCaMnO manganites, revealing phase changes driven by field-induced latent heat release, with detailed magnetization and specific heat analysis.

Contribution

It provides new insights into the first-order nature and thermal signatures of ultrasharp metamagnetic transitions in phase-separated manganites.

Findings

Observation of abrupt phase change at 2 K

Detection of specific heat discontinuities

Correlation of temperature increase with latent heat

Abstract

We investigate the behavior of ultrasharp metamagnetic transitions in La(5/8-y)Nd(y)Ca(3/8)MnO(3) manganites. These compounds change from a low temperature ferromagnetic metallic state at low Nd doping to a charge-ordered antiferromagnetic insulator for high Nd content. At an intermediate doping a phase-separated state is established. At low temperatures (2 K), we observe an avalanche-like field-induced metamagnetic transition, when the entire compound changes abruptly from one phase to the other. We investigate the signatures of this ultrasharp transition using magnetization and specific heat measurements. We observe a first order transition in the specific heat associated with discontinuous jumps in the magnetization. A strong increase of the sample temperature is simultaneously observed. The results are interpret in terms of latent heat release from the field induced enhancement of the ferromagnetic fraction, triggering the avalanche process.