Abnormal magnetic properties of MnBi thin film synthesized by MBE

State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University - Guangzhou 510275, PRC

^(a) huping8@mail.sysu.edu.cn
^(b) stslsw@mail.sysu.edu.cn

Received: 26 August 2017
Accepted: 2 October 2017

Abstract

MnBi has attracted much attention due to its unusual magnetic properties. It has the potential as an alternative to the permanent magnets containing rare-earth elements. In this paper, the MnBi thin film was grown by plasma-assisted molecular beam epitaxial technique. The as-grown film shows ferromagnetic property and an anomalous magnetization dependence on temperature. The X-ray photoelectron spectrum reveals that there are regular and interstitial sites Mn atoms with two bonding states. The observed decrease of magnetization at ∼230 K would be ascribed to the movements of Mn atoms to the interstitial sites leaving behind Mn vacancies. Also at ∼90 K, it exhibits a spin reorientation due to the magnetization change from c-axis to ab-plane which is related to the abnormal temperature dependence of the lattice parameters.