High-Pressure Suppression of Long Range Magnetic Order in the Triangular Lattice Antiferromagnet CuFeO2

TL;DR

This study demonstrates that applying high pressure suppresses long-range magnetic order in CuFeO₂, revealing an incommensurate magnetic state linked to the suppression of lattice distortion and spin frustration relief.

Contribution

It provides experimental evidence that high isotropic pressure can suppress magnetic long-range order in a triangular lattice antiferromagnet, highlighting the role of lattice distortion in magnetic ordering.

Findings

Magnetic LRO disappears at 7.9 GPa

Incommensurate order emerges under high pressure

Pressure suppresses lattice distortion that relieves spin frustration

Abstract

We succeeded in observing pressure-suppressed magnetic long range ordering (LRO) in the triangular lattice antiferromagnet CuFeO$_{2}$, using neutron diffraction experiments under an isotropic pressure. The magnetic LRO of the four-sublattice ground state under ambient pressure in CuFeO$_{2}$ almost disappears at the high pressure of 7.9 GPa, and is replaced by an incommensurate order with temperature-independent wave number of (0.192 0.192 1.5). The incommensurate wave number observed at 7.9 GPa corresponds to that observed just above the temperature at which lattice distortion and magnetic LRO simultaneously occur under ambient pressure. Therefore, the long-range magnetic ordering disappears because the high pressure suppressed the lattice distortion that otherwise relieves spin frustration and leads the spin system to LRO.