Epitaxial Growth of Altermagnet CrSb via Magnetron Sputtering

We demonstrate the epitaxial growth of NiAs-type CrSb thin films on LaAlO3(110) and Al2O3(112̅0) substrates via magnetron cosputtering, aiming to establish a platform for altermagnetism studies. Two distinct orientations─CrSb(11̅00) and CrSb(112̅0)─were realized by optimizing lattice matching and applying a W(110) buffer layer when necessary. X-ray diffraction and scanning tunneling electron microscopy (STEM) analyses confirm high crystallinity, with temperature and preannealing conditions found to critically affect film quality and phase formation. A coexistence of (11̅00) and (0001) phases was observed at elevated temperatures, accompanied by improved mosaicity. Nanobeam diffraction reveals local grain structures, while EDS confirms the near-stoichiometric composition. The hysteresis loop measurements reveal weak ferromagnetic-like signals, likely originating from interfacial defects, while no anomalous signals are observed. The minimal buffer layer requirement on insulating substrates makes the films compatible with advanced characterizations such as magnetotransport and ARPES. We believe our results offer new insight into the growth behavior of CrSb and provide a foundation for future experimental exploration of the altermagnetic materials.