Recrystallization of glass: homogeneous vs. heterogeneous nucleation in La(0.5)Ca(0.5)MnO3

TL;DR

This study investigates the kinetically arrested magnetic states in La(0.5)Ca(0.5)MnO3, revealing how heterogeneous nucleation and annealing can convert a glass-like ferromagnetic-metallic phase into an equilibrium antiferromagnetic-insulating phase.

Contribution

It presents a phenomenological understanding of the glass-like magnetic phase and demonstrates how annealing facilitates its transformation via heterogeneous nucleation.

Findings

Persistent non-ergodic FMM phase at low temperatures

Devitrification of the glass-like phase upon heating

Enhanced recrystallization with increased glass fraction

Abstract

We probe through magnetization and resistivity measurements a kinetically arrested glass-like but long-range ordered magnetic state. The transformation kinetics of the magnetic field-temperature induced broad first-order transition from ferromagnetic-metallic (FMM) to antiferromagnetic-insulating (AFI) state gets hindered at low temperature in a La(0.5)Ca(0.5)MnO3 sample. A fraction of high-temperature FMM phase persists to the lowest temperature, albeit as a non-ergodic state. We present a phenomenology for this glass-like but long-range order FMM phase which devitrifies on heating and converts to equilibrium AFI phase. The residual kinetically arrested FMM phase can be `recrystallized' to AFI state by annealing and more efficiently by successive annealing, presumably by heterogeneous nucleation. This glass-like state shows a stimulating feature that when the fraction of glass is larger the `recrystallization' is easier.