Effect of antiferromagnetic spin correlations on lattice distortion and charge ordering in Pr$_{0.5}$Ca$_{1.5}$MnO$_{4}$

TL;DR

This study uses neutron scattering to explore how antiferromagnetic spin correlations influence lattice distortion and charge ordering in Pr$_{0.5}$Ca$_{1.5}$MnO$_4$, revealing a strong spin-lattice coupling affecting low-temperature behavior.

Contribution

It demonstrates that short-range AF spin correlations suppress lattice distortion above the AF ordering temperature, highlighting the role of spin-lattice coupling in this material.

Findings

Short-range AF correlations appear between charge/orbital order and AF transition.

AF correlations suppress orthorhombic strain induced by charge/orbital order.

Spin-lattice coupling influences the low-temperature properties of the material.

Abstract

We use neutron scattering to study the lattice and magnetic structure of the layered half-doped manganite Pr$_{0.5}$Ca$_{1.5}$MnO$_4$. On cooling from high temperature, the system first becomes charge- and orbital- ordered (CO/OO) near $T_{CO}=300$ K and then develops checkerboard-like antiferromagnetic (AF) order below $T_{N}=130$ K. At temperatures above $T_{N}$ but below $T_{CO}$ ($T_N<T<T_{CO}$), the appearance of short-range AF spin correlations suppresses the CO/OO induced orthorhombic strain, contrasting with other half-doped manganites, where AF order has no observable effect on the lattice distortion. These results suggest that a strong spin-lattice coupling and the competition between AF exchange and CO/OO ordering ultimately determines the low-temperature properties of the system.