Thin epitaxial films of the Heusler compound Co2Cr0.6Fe0.4Al

We prepared thin films of the Heusler compound Co2Cr0.6Fe0.4Al with the B2 structure on a-plane (112-bar 0) Al2O3 by sputtering. Films grown at high temperatures (T>=600-bar C) on Al2O3 are fully epitaxial with the (110) and (11-bar 0) planes of the film parallel to the (112-bar 0) and (0001) planes of the substrate, respectively. These epitaxial films possess a higher surface roughness than films grown at room temperature. The films show nearly rectangular hysteresis loops with coercive fields of the order of 10mT. Magnetooptical Kerr measurements show an in-plane anisotropy of the magnetization with the easy axis in {001} direction. Hall measurements show a strong anomalous Hall effect and a weak normal Hall voltage signalling the existence of a compensated Fermi surface