Magnetic order in the chemically-substituted frustrated antiferromagnet CsCrF$_{4}$

TL;DR

This study investigates how chemical substitution affects the magnetic ground state of the frustrated antiferromagnet CsCrF4, revealing that Fe-substitution induces a different magnetic phase compared to Al-substitution and the parent compound.

Contribution

It provides the first detailed neutron diffraction analysis showing how Fe and Al substitutions alter the magnetic structures in CsCrF4, highlighting the role of chemical doping in frustrated magnetism.

Findings

Fe-substitution leads to a 120° magnetic structure with a specific propagation vector.

Al-substitution results in a quasi-120° structure with a different propagation vector.

Fe-substitution significantly changes the magnetic ground state of CsCrF4.

Abstract

The effect of chemical substitution on the ground state of the geometrically frustrated antiferromagnet CsCrF$_4$ has been investigated through a neutron powder diffraction experiment. Magnetic Fe-substituted CsCr$_{0.94}$Fe$_{0.06}$F$_{4}$ and nonmagnetic Al-substituted CsCr$_{0.98}$Al$_{0.02}$F$_{4}$ samples are measured, and magnetic Bragg peaks are clearly observed in both samples. Magnetic structure analysis revealed a 120$^{\circ}$ structure having a magnetic propagation vector $\mathbf{k}_{\rm mag}=(0,0,1/2)$ in CsCr$_{0.94}$Fe$_{0.06}$F$_{4}$. For CsCr$_{0.98}$Al$_{0.02}$F$_{4}$, a quasi-120$^{\circ}$ structure having $\mathbf{k}_{\rm mag}=(1/2,0,1/2)$ is formed. It is notable that the identified magnetic structure in CsCr$_{0.94}$Fe$_{0.06}$F$_{4}$ belongs to a different phase of ground states from those in CsCr$_{0.98}$Al$_{0.02}$F$_{4}$ and the parent CsCrF$_{4}$. These results suggest that the Fe-substitution strongly influences the ground state of CsCrF$_{4}$.