Structure and Magnetism of Epitaxial Rare-Earth-Transition-Metal Films

Strong magnetocaloric effect induced by spin reorientation transitions in epitaxial Ho thin films

“…Holmium lattice corresponds to P63/mmc space group, hexagonal close-packed structure with cell parameters: a = 3.5773 Å, b = 3.5773 Å, c = 5.6158 Å. X-ray diffraction results for Ho grown onto MgO(111) substrates with W(110) buffer layers ( Fig.1 (a)). Dominating intensity of narrow Ho(002) peak, positions of the (002) and (004) peaks coinciding with ones recorded in [17] verify single crystallinity of the film used in our experiments. The spectrum in Fig.…”

“…(1b)) and insertion in Fig.(1a). The full width at half maximum   1 was even smaller, that in [17] indicating a high degree of crystalline orientation.…”

“…Using magnetron sputtering technique, we deposited 400 nm thick Ho thin film on single crystalline MgO substrates with an intermediate buffer layer of tungsten W. Deposition of W onto MgO (100) first yields W(100) growth which sets an epitaxial growth in Ho with its c-axis (0002) normal to the sample plane. In [17] high crystallinity of the epitaxial films was confirmed by very narrow rocking curves peaks with the full width at half maximum   2 indicative of a high degree of crystalline orientation. We used the samples grown in the same machine with the same growth protocol.…”