Ultrahigh tunneling magnetoresistance in van der Waals and lateral magnetic tunnel junctions formed by intrinsic ferromagnets Li0.5CrI3 and CrI3

Two-dimensional (2D) intrinsic magnets have been used to construct magnetic tunnel junctions (MTJs) with a high tunneling magnetoresistance (TMR) ratio, including van der Waals (vdW) MTJs and lateral MTJs. In this work, we design vdW and lateral MTJs formed by a ferromagnetic (FM) CrI3 barrier and two half-metallic Li0.5CrI3 electrodes, respectively, and investigate the TMR effect of these MTJs using the non-equilibrium Green's function combined with density functional theory. Interestingly, it is found that due to the half-metallicity of the Li0.5CrI3 electrode, the total conductances of vdW and lateral MTJs for the parallel configuration (PC) of magnetizations of two electrodes are about 12 and 11 orders of magnitude larger than those for the antiparallel configuration (APC) of magnetizations of two electrodes, respectively. Consequently, the ultrahigh TMR ratios of up to 1.48x10(14) and 2.86x10(12) are achieved in the designed vdW and lateral MTJs, respectively. Remarkably, the TMR ratio of 1.48x10(14) is the highest ratio in MTJs based on 2D materials. Moreover, due to the CrI3 barrier in vdW MTJs becoming FM half-metal, the majority-spin conductance of vdW MTJs for PC of magnetizations of two electrodes is about 2 orders of magnitude larger than that of lateral MTJs, and thus, the TMR ratio of vdW MTJs is about 2 orders of magnitude larger than that of lateral MTJs. Our results suggest that vdW and lateral MTJs formed by the FM CrI3 barrier and half-metallic Li0.5CrI3 electrodes hold great potential for applications in spintronic devices.