Room-temperature ferromagnetism in two-dimensional Mn2B

Abstract

Two-dimensional magnets with long-range magnetic order are desired for their potential applications in spintronics. Here, we propose an intrinsic two-dimensional ferromagnetism in Mn2B MBene. It is shown that Mn2B is in a metallic and ferromagnetic ground state based on first-principles calculations. The magnetic anisotropy is derived mainly from both the spin-orbit coupling (SOC) and dipole-dipole interactions. Normally, the dipole-dipole interaction is significantly smaller and is often overshadowed by the SOC. Nevertheless, the dipole-dipole interaction has superseded the SOC interaction, assuming a pivotal role in shaping Mn2B's magnetic anisotropy. Eventually, the net magnetic anisotropy energy of Mn2B is −80.7 μeV per unit cell (−1.69 × 10−4 J/m2) with in-plane magnetization, due to the larger magnetic shape anisotropy. Moreover, the critical temperature is estimated to be 548 K based on the Monte Carlo simulation of Heisenberg model, which is much higher than room temperature. Our findings indicate that Mn2B is potentially useful in spintronic devices.