| 1. |
- Vlachos, A., et al.
(författare)
-
Magnetic Properties of Textured CoPd Nanocrystalline Thin Films
- 2012
-
Ingår i: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 1533-4899. ; 12:8, s. 6240-6247
-
Tidskriftsartikel (refereegranskat)abstract
- CoPd is an important nanomaterial for magnetic and magneto-optic storage of information. In this work, CoPd alloyed thin films are grown via radio frequency magnetron sputtering on silicon, glass and polyimide substrates in a vacuum chamber with base pressure of 5 x 10(-8) mbar. The films are nanocrystalline with grain size between 4 and 80 nm. The magnetic properties of thoroughly textured CoPd alloyed thin films are compared to random polycrystalline ones. Magnetization hysteresis loops recorded under fields up to 12 kOe via a home-made magneto-optic Kerr-effect magnetometer reveal strong tendency for perpendicular magnetic anisotropy for the textured film. This anisotropy leads to the formation of well-defined stripe or labyrinthine ferromagnetic domains with the local spins oriented perpendicular to the film plane. The domain patterns and the hysteresis loops are simulated with micromagnetic calculations. Finally, an induced magnetic moment of 0.44 mu B/atom is measured for Pd via X-ray magnetic circular dichroism and it is separated into spin and orbital magnetic moment contributions.
|
|
| 2. |
- Pappas, S. D., et al.
(författare)
-
Layering and temperature-dependent magnetization and anisotropy of naturally produced Ni/NiO multilayers
- 2012
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 112:5, s. 053918-
-
Tidskriftsartikel (refereegranskat)abstract
- Ni/NiO multilayers were grown by magnetron sputtering at room temperature, with the aid of the natural oxidation procedure. That is, at the end of the deposition of each single Ni layer, air is let to flow into the vacuum chamber through a leak valve. Then, a very thin NiO layer (similar to 1.2 nm) is formed. Simulated x-ray reflectivity patterns reveal that layering is excellent for individual Ni-layer thickness larger than 2.5 nm, which is attributed to the intercalation of amorphous NiO between the polycrystalline Ni layers. The magnetization of the films, measured at temperatures 5-300 K, has almost bulk-like value, whereas the films exhibit a trend to perpendicular magnetic anisotropy (PMA) with an unusual significant positive interface anisotropy contribution, which presents a weak temperature dependence. The power-law behavior of the multilayers indicates a non-negligible contribution of higher order anisotropies in the uniaxial anisotropy. Bloch-law fittings for the temperature dependence of the magnetization in the spin-wave regime show that the magnetization in the multilayers decreases faster as a function of temperature than the one of bulk Ni. Finally, when the individual Ni-layer thickness decreases below 2 nm, the multilayer stacking vanishes, resulting in a dramatic decrease of the interface magnetic anisotropy and consequently in a decrease of the perpendicular magnetic anisotropy. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4750026]
|
|
