Crystal growth and magnetic evolution of antiferromagnetic topological insulator Zn-doped MnBi2Te4

As the first intrinsic magnetic topological insulator, MnBi2Te4 has provided a material platform for the realization of various novel physical phenomena arising from the interaction between magnetism and band topology. Here, transition element Zn-doped MnBi2Te4 crystals of millimeter size, synthesized by using self-flux method, are reported. With increasing Zn content, the hexagonal lattice shrinks, and the Raman frequencies show a red shift. All samples undergo a transition from A-type antiferromagnetic (A-AFM) to canted antiferromagnetic (CAFM) to ferromagnetic (FM) under magnetic field. The antiferromagnetic ordering temperature slightly increases from 24.2 K for MnBi2Te4 to 25.2 K for Mn0.75Zn0.25Bi2Te4. The transition field from AFM to CAFM decreases from 3.4 T for x = 0-3.07 T for x = 0.25. Isothermal magnetization data suggest that the single-ion anisotropy of Mn2+ decrease and the interlayer magnetic interaction increase slightly due to the diluted magnetic ions and unit cell shrinkage. Samples Mn0.9Zn0.1Bi2Te4 and Mn0.8Zn0.2Bi2Te4 show metallic conduction with a cusplike anomaly at around TN approximate to 24 K, corresponding to a long-range antiferromagnetic (AFM) transition. The increase of TN and decrease of transition field (HcSF) upon Zn doping, make it possible to manipulate magnetic and electrical properties in topological insulators by non-magnetic element substitution, which is of great significance for further application in quantum information storage and spintronics.