Prolonged mixed phase induced by high pressure in MnRuP

TL;DR

This study reveals a prolonged mixed phase of MnRuP under high pressure, showing a pressure-induced structural transition with magnetic origins and stability of the orthorhombic phase up to very high pressures.

Contribution

It uncovers the extended coexistence of phases in MnRuP under pressure and links structural changes to magnetic interactions, supported by experimental and theoretical analysis.

Findings

Partial phase transition from hexagonal to orthorhombic begins at 11 GPa.

Orthorhombic phase persists over a 50 GPa pressure range.

Orthorhombic phase remains stable up to ~250 GPa in theory.

Abstract

Hexagonally structured MnRuP was studied under high pressure up to 35 GPa from 5 to 300 K using synchrotron X-ray diffraction. We observed that a partial phase transition from hexagonal to orthorhombic symmetry started at 11 GPa. The new and denser orthorhombic phase coexisted with its parent phase for an unusually long pressure range, {\Delta}P ~ 50 GPa. We attribute this structural transformation to a magnetic origin, where a decisive criterion for the boundary of the mixed phase lays in the different distances between the Mn-Mn atoms. In addition, our theoretical study shows that the orthorhombic phase of MnRuP remains steady even at very high pressures up to ~ 250 GPa, when it should transform to a new tetragonal phase.