Measurement of the magnetic octupole susceptibility of PrV<sub>2</sub>Al<sub>20</sub>.

Ye, Linda; Sorensen, Matthew E; Bachmann, Maja D; Fisher, Ian R · Nat Commun · 2024

basic_science · Level V

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Abstract

Revealing the presence of magnetic octupole order and associated octupole fluctuations in solids is a highly challenging task due to the lack of simple external fields that can couple to magnetic octupoles. Here, we demonstrate a methodology for probing the magnetic octupole susceptibility of a candidate material, PrV<sub>2</sub>Al<sub>20</sub>, using a product of magnetic field H<sub>i</sub> and shear strain ϵ<sub>jk</sub> as a composite effective field, while employing an adiabatic elastocaloric effect to probe the response. We observe Curie-Weiss behavior in the obtained octupolar susceptibility down to approximately 3 K. Although octupole order does not appear to be the leading multipolar channel in PrV<sub>2</sub>Al<sub>20</sub>, our results nevertheless reveal the presence of strong magnetic octupole fluctuations and hence demonstrate that octupole order is at least a competing state. More broadly, our results highlight how anisotropic strain can be combined with magnetic fields to probe elusive 'hidden' electronic orders.