Dirty Peierls transition to stripe phase in manganites

TL;DR

This study investigates the phase transition to stripe order in manganites, revealing it as a second-order 'dirty' Peierls transition and discovering an unexpected magnetic phase in low-temperature Pr-based manganite.

Contribution

It demonstrates that the stripe phase transition in manganites can be modeled as a 'dirty' Peierls transition and uncovers a new magnetic phase in Pr$_{0.48}$Ca$_{0.52}$MnO$_3$.

Findings

Stripe phase transition is second order.

'Dirty' Peierls transition model fits well.

Unanticipated magnetic phase in Pr-based manganite.

Abstract

The nature of the phase transitions in La$_{1-x}$Ca$_x$MnO$_3$ and Pr$_{0.48}$Ca$_{0.52}$MnO$_3$ has been probed using heat capacity and magnetisation measurements. The phase transition associated with the onset of the stripe phase has been identified as second order. The model of a Peierls transition in a disordered system (a `dirty' Peierls transition) is shown to provide an extremely good fit to this transition. In addition, an unexpected magnetic phase has been revealed in low temperature Pr$_{0.48}$Ca$_{0.52}$MnO$_3$, associated with an excess heat capacity over a wide temperature range compared to La$_{1-x}$Ca$_x$MnO$_3$.