Influence of growth morphology on the Neel temperature of CrRu thin films and heterostructures

[摘要] Dimensionality effects on epitaxial and polycrystalline Cr1-xRux alloy thin films and in Cr/Cr-Ru heterostructures are reported. X-ray analysis on Cr0.9965Ru0.0035 epitaxial films indicates an increase in the coherence length in growth directions (100) and (110) with increasing thickness (d), in the range 20 <= d <= 300 nm. Atomic force microscopy studies on these films shows pronounced vertical growth for d>50 nm, resulting in the formation of columnar structures. The Neel temperatures (T-N) of the Cr0.9965Ru0.0035 films show anomalous behaviour as a function of d at thickness d approximate to 50 nm. It is interesting to note that this thickness corresponds to that for which a change in film morphology occurs. Experiments on epitaxial Cr1-xRux thin films, with 0 <= x <= 0.013 and d = 50 nm, give T-N-x curves that correspond well with that of bulk Cr1-xRux alloys. Studies on Cr/Cr0.9965Ru0.0035 superlattices prepared on MgO(1 0 0), with the Cr layer thickness varied between 10 and 50 nm, keeping the Cr0.9965Ru0.0035 thickness constant at 10 nm, indicate a sharp decrease in T-N as the Cr separation layers reaches a thickness of 30 nm; ascribed to spin density wave pinning in the Cr layers for d<30 nm by the adjacent CrRu layers. (C) 2009 Elsevier B.V. All rights reserved.

[发布日期] 2010-05-01

[效力级别]  Proceedings Paper

[关键词] Cr alloy;Epitaxial thin film;Heterostructure;Spin density wave;Electrical resistivity