Magnetic anisotropy in nanostructured gadolinium

This experimental work evaluates the magnetic response of 25-nm-thick Gd thin film and 1400 x 70 x 50 nm(3) Gd nanobar structures. Neither the thin film nor the nanobars exhibited single domain behavior at temperatures down to 53 K. The Gd thin film exhibited a magnetocrystalline anisotropy induced spin-reorientation due to a hexagonal close-packed (002) texture, something different from that previously reported on epitaxial Gd thin film. The discrepancy is due to grain boundary induced spin-disorder in the nanosacle. The Gd nanobars had a saturation magnetization 75% smaller than the thin film or bulk and is attributed to oxidation as well as the crystallinity changes from hexagonal close-packed to face-centered cubic caused by stress induced stacking faults. These experimental results for both thin film and nanobar show that the crystallinity has a substantial impact to the magnetic anisotropy of Gd nanostructures as well as the formation of single domain structures. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3691220]