Transport properties of crystallized antiferromagnetic MnBi 2 Te 4 thin films grown by magnetron sputtering

The intrinsic magnetic topological insulator MnBi 2 Te 4 has drawn great attention due to its novel quantum states, among which the most promising one is the quantum anomalous Hall effect. However, MnBi 2 Te 4 is a metastable phase with a narrow temperature range for synthesis, which remains a challenge to grow uniform and high quality MnBi 2 Te 4 sample. Large-area MnBi 2 Te 4 thin films are mainly prepared by molecular beam epitaxy so far. Here, we report a highly versatile method for growing crystallized MnBi 2 Te 4 films on amorphous SiO 2 /Si substrates by magnetron sputtering at room temperature and post-annealing. High-quality MnBi 2 Te 4 films with a c -axis perpendicular to the substrate and low surface roughness are realized. MnBi 2 Te 4 films have an antiferromagnetic Néel temperature of 21 K, with low carrier concentration (2.5 × 10 19 cm −3 ) and decent mobility (34 cm 2 V −1 s −1 ). The films reveal ferromagnetic at ground state and a typical spin-flop transition at 2–3 T. This work provides a pathway toward the fabrication of sputtered-MnBi 2 Te 4 devices for electronic and spintronic applications.