High pressure magnetic state of MnP probed by means of muon-spin rotation

TL;DR

This study uses muon-spin rotation to investigate how pressure affects magnetic states in MnP, revealing transitions between ferromagnetic and helical phases, and suggesting superconductivity emerges from an incommensurate helical magnetic state.

Contribution

It provides detailed insights into the pressure-dependent magnetic phases of MnP using muon-spin rotation, identifying multiple magnetic states and their transitions.

Findings

Identification of ferromagnetic and two helical magnetic states.

Observation of first order phase transitions between magnetic states.

Superconductivity likely develops from an incommensurate helical phase.

Abstract

We report a detailed $\mu$SR study of the pressure evolution of the magnetic order in the manganese based pnictide MnP, which has been recently found to undergo a superconducting transition under pressure once the magnetic ground state is suppressed. Using the muon as a volume sensitive local magnetic probe, we identify a ferromagnetic state as well as two incommensurate helical states (with propagation vectors ${\bf Q}$ aligned along the crystallographic $c-$ and $b-$directions, respectively) which transform into each other through first order phase transitions as a function of pressure and temperature. Our data appear to support that the magnetic state from which superconductivity develops at higher pressures is an incommensurate helical phase.