Chirality memory stored in magnetic domain walls in the ferromagnetic state of MnP

TL;DR

This study demonstrates that magnetic chirality information in MnP is retained across phase transitions and can be manipulated via magnetic fields, revealing a form of chirality memory stored in ferromagnetic domain walls.

Contribution

It shows that chirality memory persists in MnP across phase transitions and is stored in ferromagnetic domain walls, a novel insight into magnetic chirality behavior.

Findings

Chirality information remains after phase transition to ferromagnetic state.

Magnetic field can quench the chirality-induced resistivity.

Chirality memory is stored in ferromagnetic domain walls.

Abstract

Chirality in a helimagnetic structure is determined by the sense of magnetic moment rotation. We found that the chiral information did not disappear even after the phase transition to the high-temperature ferromagnetic phase in a helimagnet MnP. The 2nd harmonic resistivity $\rho^{\rm 2f}$, which reflects the breaking down of mirror symmetry, was found to be almost unchanged after heating the sample above the ferromagnetic transition temperature and cooling it back to the helimagnetic state. The application of a magnetic field along the easy axis in the ferromagnetic state quenched the chirality-induced $\rho^{\rm 2f}$. This indicates that the chirality memory effect originated from the ferromagnetic domain walls.