Probing Ferrimagnetic Semiconductor with Enhanced Negative Magnetoresistance: 2D Chromium Sulfide

Magnetic 2D materials have emerged as a great interest in spintronics due to atomic thickness scaling, low energy switching, and ease in the manipulation of spins. This report demonstrates a facile, bottom-up, chemical vapor deposition approach for non-van der Waals (non-vdWs), 2D chromium (III) sulfide (Cr2S3) with c-axis orientation, out-of-plane magnetic anisotropy (easy axis), and ferrimagnetic ordering. Importantly, the anisotropic magnetic saturation and resistivity of 10.23 mΩ cm reveal a narrow bandgap ferrimagnetism in Cr2S3 (∆EActivation ≈ 22 meV and Eg ≈ 40 meV). The prototype lateral spin-channel Al/Cr2S3/Al devices exhibit a negative magnetoresistance of ≈25% and ≈15% at 100 K (below Néel temperature) for few-layer (≈8 nm) and thin-film (≈50 nm) device structures, respectively, owing to itinerant ferrimagnetism of Cr2S3. The magnetic field-induced spin polaron formations are quite resilient and enhance the field-dependent carrier conduction, making it greatly useful for negative magnetoresistance operation. These prototype Al/Cr2S3/Al structures have demonstrated a low power (≈2 µW for 8 µm channel at 10 µA current) operation with a negative field-dependent resistance coefficient (rM) of ≈−5 × 10−4 Oe−1. The computed rM magnitude is tenfold higher than the bulk Cr2S3. This study identifies the potential of non-vdW Cr2S3 toward new and robust 2D-based spintronic applications.