Glassy magnetic ground state in layered compound MnSb2Te4

Abstract

As a sister compound of MnBi2Te4, the high-quality MnSb2Te4 single crystals are grown via solid-state reaction where prolonged annealing and narrow temperature window play critical roles on account of its thermal metastability. Single-crystal X-ray diffraction (SCXRD) analysis on MnSb2Te4 illustrates a crystal model that is isostructural to MnBi2Te4, consisting of Te-Sb-Te-Mn-Te-Sb-Te septuple layers (SLs) stacking in an ABC sequence. However, MnSb2Te4 reveals a more pronounced cation intermixing in comparison with MnBi2Te4, comprising 28.9(7)% Sb antisite defects on the Mn (3a) site and 19.3(6)% Mn antisite defects on the Sb (6c) site, which may give rise to novel magnetic properties in emerging layered MnBi2Te4-family materials. Unlike the antiferromagnetic (AFM) nature in MnBi2Te4, MnSb2Te4 exhibits a glassy magnetic ground state below 24 K and can be easily tuned to a ferromagnetic state under a weak applied magnetic field. Its magnetic hysteresis, anisotropy, and relaxation process are investigated in detail via static and dynamic magnetization measurements. Moreover, anomalous Hall effect as a p-type conductor is demonstrated with transport measurements. This work grants MnSb2Te4 a possible access to the future exploration of exotic quantum physics by removing the odd/even layer number restraint in realizing quantum transport phenomena in intrinsic AFM MnBi2Te4-family materials, as a result of the crossover between its magnetism and potential topology arising from the Sb-Te layer.