High quality epitaxial Mn_2Au (001) thin films grown by molecular beam epitaxy

摘要

The recently discovered phenomenon of Neel spin-orbit torque in antiferromagnetic Mn_2Au [Bodnar et al., Nat. Commun. 9, 348 (2018); Meinert et al, Phys. Rev. Appl. 9, 064040 (2018); Bodnar et al, Phys. Rev. B 99, 140409(R) (2019)] has generated huge interest in this material for spintronics applications. In this paper, we report the preparation and characterization of high quality Mn_2Au thin films by molecular beam epitaxy and compare them with magnetron sputtered samples. The films were characterized for their structural and morphological properties using reflective high-energy electron diffraction, x-ray diffraction, x-ray reflectometry, atomic force microscopy, and temperature dependent resistance measurements. The thin film composition was determined using both inductively coupled plasma optical emission spectroscopy and Rutherford backscattering spectrometry techniques. The MBE-grown films were found to show a superior smooth morphology and a low defect concentration, resulting in reduced scattering of the charge carriers.