Tailoring MBE Growth of c-Mn3Sn Directly on MgO (111): From Islands to Film

We present our study of (0001) oriented Mn$_3$Sn (c-Mn$_3$Sn) thin films synthesized directly on an MgO (111) substrate via molecular beam epitaxy. We identify a growth window where Mn$_3$Sn growth can be controlled through slight adjustments of the Mn flux, achieving either $\mu$m$^2$-sized high crystalline-quality islands or an almost completely continuous film. High-resolution X-ray diffraction results indicate that both films are highly (0001) oriented. The atomic resolution images show clear film-substrate interfaces displaying an epitaxial relationship. Scanning precession electron diffraction measurements reveal that the island featured sample has highly crystallized Mn$_3$Sn. The sample featuring a high continuity exhibits defects in some areas but retains the dominant Mn$_3$Sn structure. This work demonstrates a potential method for synthesizing high crystalline-quality Mn$_3$Sn films with substantial coverage, facilitating the study of Mn3Sn films without the influence of an additional buffer layer and promoting their application in integrated spintronics.