Novel Magnetic Chiral Structures and Unusual Temperature Hysteresis in the Metallic Helimagnet MnP

TL;DR

This study reveals complex magnetic structures and unusual temperature hysteresis in MnP, including a tilted helimagnetic phase and a stripe domain formation, advancing understanding of magnetic phase transitions in metallic helimagnets.

Contribution

It demonstrates the existence of a modified tilted helimagnetic structure and identifies a novel weak ferromagnetic phase with hysteresis, revealing new magnetic phenomena in MnP.

Findings

Modified tilted helimagnetic structure due to Dzyaloshinsky-Moriya interaction

Discovery of two distinct weak ferromagnetic states (LM and SM)

Unusual temperature hysteresis explained by stripe domain formation

Abstract

We have reinvestigated the magnetic properties of the classical metallic helimagnet MnP by magnetization and neutron scattering experiments. Our neutron scattering results indicate that the previously reported magnetic structure in the low-temperature (LT) helimagnetic phase (T < 47K) should be modified to an alternately tilted helimagnetic structure pro- duced by the Dzyaloshinsky-Moriya interaction. In the intermediate temperature (IT) range between the LT helimagnetic phase and the high-temperature (HT) ferromagnetic phase along the c-axis, 47K < T < 282K, we have found a weak ferromagnetic behavior along the b-axis. Surprisingly, the IT weak ferromagnetic phase has two different states, namely, the large magnetization (LM) and small magnetization (SM) states. The SM state emerges with cooling from the paramagnetic phase above 292 K via the HT ferromagnetic phase and LM state emerges with warming from the LT helimagnetic phase. The weak ferromagnetism along the b-axis and the unusual temperature hysteresis in the IT phase can be understood by assuming a spontaneous formation of the stripe structure consisting of alternately arranged HT ferromagnetic and LT helimagnetic domains.