Anomalous phase of MnP at very low field

TL;DR

This study investigates a newly observed low-field magnetic phase in MnP, revealing its complex nature and relation to existing magnetic structures through detailed magnetization measurements.

Contribution

The paper identifies and characterizes a novel magnetic phase in MnP at very low fields, providing insights into its hysteresis and relation to known magnetic phases.

Findings

Divergent AC susceptibility at T* indicating phase transition

Sharp increase in DC magnetization at T*

Temperature hysteresis linked to magnetic state history

Abstract

Manganese phosphide MnP has been investigated for decades because of its rich magnetic phase diagram. It is well known that the MnP exhibits the ferromagnetic phase transition at $\Tc=292$ K and the helical magnetic phase below $\TN=47$ K at zero field. Recently, a novel magnetic phase transition was observed at $T^* = 282$ K when the magnetic field is lower than 5 Oe. However, the nature of the new phase has not been illuminated yet. In order to reveal it, we performed the AC and the DC magnetization measurements for a single crystal MnP at very low field. A divergent behavior of the real and the imaginary part of the AC susceptibility and a sharp increase of the DC magnetization was observed at $T^*$, indicating the magnetic phase transition at $T^*$. Furthermore a peculiar temperature hysteresis was observed: namely, the magnetization depends on whether cooling sample to the temperature lower than $\TN$ or not before the measurements. This hysteresis phenomenon suggests the complicated nature of the new phase and a strong relation between the magnetic state of the new phase and the helical structure.