Controllable synthesis of two-dimensional magnetic FeS nanoplates with high Curie temperature and unique magnetotransport properties

Abstract

The discovery of magnetic two-dimensional materials has ignited intensive research interest for the potential development in innovative spintronic devices. Herein, ultrathin FeS nanoplates with various thicknesses are obtained through a chemical vapor deposition method and their magnetic properties are comprehensively studied. The obtained material displays trapezoidal shapes on SiO2/Si substrate and triangular shapes on large-area WSe2 nanosheets. A high degree of crystallinity and flat surface of FeS nanoplates are verified by Raman spectra, X-ray photoelectron spectroscopy analysis, X-ray diffraction patterns and annular dark-field aberration-corrected scanning transmission electron microscopy. Then magneto-transport studies illustrate that the resistance displays a bowtie shape after sweeping a full cycle of magnetic fields, which shows a decreasing trend with an increasing temperature but persists to 300 K. Thickness-dependent analysis demonstrates that the bowtie shape of resistance gradually reduces as the thickness of nanoplates increases. Angle-dependent measurements reveal that resistance shows apparent anisotropic properties. At last, vibrating sample magnetometer results show as-grown FeS nanoplates feature magnetism at room temperature. Our study demonstrates that FeS nanoplates grown by chemical vapor deposition methods provide an ideal system to research magnetic properties at the two-dimensional limit, providing new opportunities for the next-generation spintronic devices.