Pressure-induced collapse of ferromagnetism in Nickel

TL;DR

This study uses first-principles calculations to demonstrate that high pressure causes a sudden loss of ferromagnetism in nickel without any structural change, due to increased crystal field splitting and altered electronic interactions.

Contribution

It provides a detailed first-principles explanation for pressure-induced magnetization collapse in nickel, highlighting the role of crystal field effects and next-nearest neighbor interactions.

Findings

Magnetization drops abruptly at high pressure in Ni.

No structural phase transition occurs during magnetization collapse.

Enhanced crystal field splitting drives the system beyond the Stoner Criterion.

Abstract

Transition metals, Fe, Co and Ni, are the canonical systems for studying the effect of external perturbations on ferromagnetism. Among these, Ni stands out as it undergoes no structural phase transition under pressure. Here we have investigated the long-debated issue of pressure-induced magnetisation drop in Ni from first-principles. Our calculations confirm an abrupt quenching of magnetisation at high pressures, not associated with any structural phase transition. We find that the pressure substantially enhances the crystal field splitting of Ni-$3d$ orbitals, driving the system towards a new metallic phase violating the Stoner Criterion for ferromagnetic ordering. Analysing the charge populations in each spin channel, we show that the next nearest neighbour interactions play a crucial role in quenching ferromagnetic ordering in Ni and materials alike.