Magnetic Properties of Dy Thin Films Grown on Al2O3 Substrates with Different Crystallographic Orientations.

Using high-vacuum magnetron sputtering, epitaxial Dy films were synthesized on Nb and Ta buffer layers on single-crystal Al₂O₃ substrates with different crystallographic orientations. It was established that the epitaxial relationships [11 0]Al₂O₃|| [011]Nb(Ta) and [1 02]Al₂O₃||[011]Nb(Ta) are satisfied with growing a Nb(Ta) buffer layer on single-crystal sapphire substrates with different crystallographic orientations. The second relationship has never been observed up to now; this may be because the growth rates upon magnetron sputtering are approximately two orders higher than those upon molecular-beam epitaxy. It was established that the Dy crystal lattice expansion in the basal plane by 2.8–3% occurs in all cases. Contrary to the samples grown on Nb, the Dy films grown on the Ta buffer layers are characterized by a larger value of the saturation magnetization, whereas its maximum value is attained in the polycrystalline Dy films. [ABSTRACT FROM AUTHOR]