Tuning the critical magnetic field of the triplon Bose-Einstein condensation in Ba$_{3-x}$Sr$_x$Cr$_2$O$_8$

TL;DR

This study investigates how the critical magnetic field for triplon Bose-Einstein condensation varies in the Ba$_{3-x}$Sr$_x$Cr$_2$O$_8$ solid solution, revealing a monotonic decrease with increasing Sr content through high-field experiments.

Contribution

It provides systematic experimental data on the magnetic properties of Ba$_{3-x}$Sr$_x$Cr$_2$O$_8$ across different compositions, linking critical field changes to magnetic interactions.

Findings

Critical fields decrease monotonically with Sr content.

Experimental results align with previous magnetic interaction variations.

High-field magnetometry effectively probes triplon condensation.

Abstract

The structure and magnetic interactions of the triplon Bose-Einstein condensation candidates Ba$_3$Cr$_2$O$_8$ and Sr$_3$Cr$_2$O$_8$ have been studied thoroughly in the literature, but little is known about a possible triplon condensation in the corresponding solid solution Ba$_{3-x}$Sr$_x$Cr$_2$O$_8$. We have prepared various members of this solid solution and systematically examined their magnetic properties in high magnetic fields up to 60 T and at low temperatures down to 340 mK, by means of pulsed field and cantilever magnetometry. From these experiments for $x\in\{3,2.9,2.8,2.7,2.6,2.5\}$, we find that the critical fields of Ba$_{3-x}$Sr$_x$Cr$_2$O$_8$ decrease monotonically as a function of the Sr content $x$. This change is in good agreement with the earlier reported variation of the magnetic interactions in these compounds.