Layer dependent magnetoresistance of vertical MoS2 magnetic tunnel junctions

Abstract

Spin polarization of electrons through transition metal dichalcogenides (TMDs) from ferromagnetic metals (FMs) is a fascinating phenomenon in condensed matter physics. The spin polarized current makes high- and low-resistance states in FM/TMDs/FM junctions depending on magnetization alignment of FM electrodes. We have manifested vertical spin valve junctions by incorporating MoS₂ layers of different thicknesses by an ultraclean fabrication method. The current–voltage (I–V) characteristics show the ohmic contact behavior, indicating that mono-, bi-, and tri-layer MoS₂ work as conducting thin film. In contrast, FM/multilayer MoS₂/FM junction shows non-linear I–V characteristics and the junction resistance increases as the temperature is lowered, indicating that multilayer MoS₂ provides a tunneling barrier between FM electrodes. We have found that the magnetoresistance (MR) ratio increases gradually as the thickness of the MoS₂ layer is increased. Our investigation will provide a guide to make an optimal choice in the development of magnetic tunnel junctions with two-dimensional layered TMDs.