Thermal stability of metastable, epitaxial PrCo7 films with high energy density

Abstract

Two series of epitaxial Pr–Co thin films with a nominal composition of Pr2Co17 were grown on Cr buffered MgO(1 1 0) single crystal substrates by pulsed laser deposition, in which the deposition temperature TD and the post annealing temperature Tann were varied. Pr–Co films prepared at different deposition temperatures crystallize in the metastable PrCo7 structure (TbCu7 type) for 450 °C ≤ TD ≤ 650 °C. For TD ≤ 600 °C these films exhibit a (h 0 0) texture, with the c-axis of the Pr–Co grain aligned in the substrate plane along MgO[0 0 1]. However, raising TD to 650 °C, an additional out-of-plane c-axis texture is observed. Post annealing experiments on films, which are deposited at 450 °C to obtain the unique in-plane texture, reveal that crystal structure, texture and also the uniaxial magnetocrystalline anisotropy of the metastable PrCo7 structure is maintained for annealing temperatures up to 800 °C. The influence of deposition temperature and post annealing temperature on phase stability and extrinsic magnetic properties are discussed.