# Evolution of spin correlations in SrDy2O4 in an applied magnetic field

## TL;DR

This study investigates how magnetic order develops in SrDy2O4 under an applied magnetic field, revealing complex magnetic structures and partial ordering due to the material's frustrated lattice and anisotropic properties.

## Contribution

It provides detailed neutron diffraction analysis of magnetic order evolution in SrDy2O4, highlighting the effects of magnetic fields on short- and long-range correlations in a frustrated system.

## Key findings

- Zero-field state has no long-range order, only diffuse scattering.
- Moderate magnetic field induces a 1/3-magnetisation plateau with increased correlations.
- Fields above 2.5 T produce ferromagnetic peaks indicating significant magnetic ordering.

## Abstract

The development of short- and long-range magnetic order induced in a frustrated zig-zag ladder compound SrDy2O4 by an applied field is studied using neutron diffraction techniques. In zero field, SrDy2O4 lacks long-range magnetic order down to temperatures as low as 60 mK, and the observed powder neutron diffraction (PND) patterns are dominated by very broad diffuse scattering peaks. Single crystal neutron diffraction reveals that the zero-field magnetic structure consists of a collection of antiferromagnetic chains running along the c axis and that there is very little correlation between the chains in the ab plane. In an applied magnetic field, the broad diffuse scattering features in PND are gradually replaced by much sharper peaks, however, the pattern remains rather complex, reflecting the highly anisotropic nature of SrDy2O4. Single crystal neutron diffraction shows that a moderate field applied along the b axis induces an up-up-down magnetic order associated with a 1/3-magnetisation plateau, in which magnetic correlation length in the ab plane is significantly increased, but it nevertheless remains finite. The resolution limited k = 0 peaks associated with a ferromagnetic arrangement appear in powder and single crystal neutron diffraction patterns in fields of 2.5 T and above.