Abstract
We report on ultrasonic and magnetocaloric-effect measurements of the hexagonal antiferromagnet having a distorted kagome lattice. We observed a pronounced softening of the transverse modulus, , above 30 T applied along [100], indicating an as-yet-unidentified magnetic field induced phase transition. We determined the field-temperature phase diagrams using pulsed magnetic fields up to 55.2 T, applied along [100] and [001]. Optimizing crystal-electric-field parameters within the mean-field approximation, we conclude that the enhancement of the field induced phase-transition temperature is due to electric quadrupolar and magnetic octupolar mediated interactions. We propose that the order parameter of the magnetic field induced phase transitions is the electric quadrupole , facilitated by octupole-mediated interactions.
- Received 2 April 2023
- Accepted 9 May 2023
DOI:https://doi.org/10.1103/PhysRevB.107.205136
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