Stabilization of the collinear plateau phase by thermal fluctuations in the disordered triangular lattice antiferromagnet Rb$_{(1-x)}$K$_{x}$Fe(MoO$_4$)$_2$

V. N. Glazkov; I. A. Krastilevskiy

paper

Stabilization of the collinear plateau phase by thermal fluctuations in the disordered triangular lattice antiferromagnet Rb $_{(1 - x)}$ K $_{x}$ Fe(MoO $_{4}$ ) $_{2}$

arXiv:2507.19190

Abstract

The triangular lattice antiferromagnet RbFe(MoO $_{4}$ ) $_{2}$ orders antiferromagnetically in a planar 120 $^{\circ}$ -structure below $T_{N} \approx 4$ K. A striking feature of RbFe(MoO $_{4}$ ) $_{2}$ magnetic phase diagram is the presence of collinear ``1/3-plateau'' magnetic phase, which is stabilized by thermal and quantum fluctuations at magnetization $M \approx \frac{1}{3} M_{sat}$ . Static disorder caused by impurities is predicted to act against the effect of fluctuations and to suppress collinear plateau phase (Maryasin and Zhitomirsky, PRL 111, 247201 (2013)). Balance between ``dynamic'' thermal and quantum fluctuations and ``static'' impurity-induced disorder is temperature-sensitive, which allows thermal fluctuations to take over the effect of static disorder and leads to the revival of the fluctuation-stabilized ``1/3-plateau'' phase on heating. Here we present experimental results directly confirming this prediction and demonstrating re-establishment of the plateau-like phase in the diluted Rb $_{(1 - x)}$ K $_{x}$ Fe(MoO $_{4}$ ) $_{2}$ sample at moderate dilution level $x = 15$ \% on heating as the effect of thermal fluctuations increases.

10 pages, 8 figures

Stabilization of the collinear plateau phase by thermal fluctuations in the disordered triangular lattice antiferromagnet Rb(1−x)​Kx​Fe(MoO4​)2​

Abstract

Stabilization of the collinear plateau phase by thermal fluctuations in the disordered triangular lattice antiferromagnet Rb $_{(1 - x)}$ K $_{x}$ Fe(MoO $_{4}$ ) $_{2}$