Cascade of field-induced magnetic transitions in a frustrated antiferromagnetic metal

TL;DR

This study investigates the complex magnetic phase transitions in a frustrated metallic antiferromagnet under high magnetic fields, revealing a cascade of phases and the influence of itinerant electrons on the magnetic behavior.

Contribution

It provides the first detailed phase diagram of a frustrated itinerant-electron antiferromagnet under high magnetic fields, highlighting deviations from localized moment models due to electron itinerancy.

Findings

Observed multiple magnetic phase transitions up to 90 T

Constructed a detailed field-temperature phase diagram

Identified deviations from localized moment model predictions

Abstract

Frustrated magnets can exhibit many novel forms of order when exposed to high magnetic fields, however, much less is known about materials where frustration occurs in the presence of itinerant electrons. Here we report thermodynamic and transport measurements on micron-sized single crystals of the triangular-lattice metallic antiferromagnet 2H-AgNiO2, in magnetic fields of up to 90 T and temperatures down to 0.35 K. We observe a cascade of magnetic phase transitions at 13.5 20, 28 and 39T in fields applied along the easy axis, and we combine magnetic torque, specific heat and transport data to construct the field-temperature phase diagram. The results are discussed in the context of a frustrated easy-axis Heisenberg model for the localized moments where intermediate applied magnetic fields are predicted to stabilize a magnetic supersolid phase. Deviations in the measured phase diagram from this model predictions are attributed to the role played by the itinerant electrons.