Evolution of magnetic interactions in a pressure-induced Jahn-Teller driven magnetic dimensionality switch

TL;DR

This study investigates how applying pressure induces a transition from a two-dimensional to a one-dimensional antiferromagnetic phase in a coordination polymer, revealing structural and magnetic property changes.

Contribution

It demonstrates pressure-driven magnetic dimensionality switching linked to Jahn-Teller axis rotation and structural modifications in a coordination polymer.

Findings

Transition from 2D to 1D antiferromagnetic phase at 9.1 kbar

Magnetic exchange energy J halves and T_N decreases fivefold with pressure

Magnetic dimensionality change correlates with structural pressure effects

Abstract

We present the results of high-field magnetization and muon-spin relaxation measurements on the coordination polymer CuF_2(H_2O)_2(pyrazine) in pressures up to 22.5 kbar. We observe a transition from a quasi-two-dimensional to a quasi-one-dimensional antiferromagnetic phase at 9.1 kbar, driven by a rotation of the Jahn-Teller axis. Long-range antiferromagnetic ordering is seen in both regimes, as well as a phase separation in the critical pressure region. The magnetic dimensionality switching as pressure is increased is accompanied by a halving of the primary magnetic exchange energy J and a fivefold decrease in the ordering temperature T_N. J decreases gradually with pressure in the two-dimensional phase, and then increases in the one-dimensional regime. We relate both effects to the changes in the crystal structure with applied pressure.