Visualizing Two Subsequent Magnetic Phase Transitions in a Helimagnet Candidate

Helimagnetism provides new opportunities in spintronic applications. This magnetic phase develops upon the competitions between different types of magnetic exchange couplings, for example, between the symmetric ferromagnetic coupling and the antisymmetric Dzyaloshinskii–Moriya (DM) interaction. Chiral crystal structure is one venue to turn on the DM interactions, and thus, intercalated transition metal dichalcogenides (TMDCs) of chiral structure are a recent platform to realize the structural chirality-induced magnetic helicity. Despite the creation of helimagnetic orders in intercalated TMDCs, the magnetic phase transition and the helimagnetic domain distribution remain elusive. In this presentation, we will use second harmonic generation spectroscopy and microscopy to study a Cr1/3NbS2. We will show the experimental data on the two magnetic phase transitions, six helimagnetic domain states, and the interplay between structural chirality and magnetic helicity. We will discuss the potential origins for the multi-stage phase transitions and multi-domain states in Cr1/3NbS2.