Magnetic properties of granular CoCrPt:SiO₂thin films deposited on GaSb nanocones

Abstract

We report on the effect of microstructure and geometrically induced modifications of the magnetic properties of granular CoCrPt:SiO2 films with weakly interacting magnetic grains deposited on pre-structured GaSb nanocone templates fabricated by an ion erosion technique. By tuning the irradiation conditions, nanocone patterns of different cone sizes were prepared (from 28 to 120 nm in diameter and 32 to 330 nm high, respectively). The influence of the intergranular exchange coupling was also investigated by varying the SiO2 content from 8 to 12 at.%. Deposition of CoCrPt:SiO2 on samples with small nanocones leads to a close magnetic grain packing, which results in the formation of extended magnetic domains larger than the average distance between the GaSb cones. In contrast, on larger nanocones, the magnetic coating grows on the side-walls, with a large separation between neighboring cones, leading to magnetic single-domain regions, which are correlated to the underlying structure. Magnetometry indicates that both remanence and coercivity decrease with increasing cone size and/or SiO2 content due to a combined effect of the angular distribution of the magnetic easy axis of the grains and the intergranular exchange coupling strength.

Engineering Curvature-Induced Anisotropy in Thin Ferromagnetic Films

“…Generally, the magnetic systems studied in Ref. [38] may be excellent candidates for the curvature-induced anisotropy engineering.…”

Ion Beam Nanopatterning of Biomaterial Surfaces

“…In general, normalincidence deposition is preferred, as deposition under an oblique angle of incidence may result in material accumulation on the pattern crests, leading to non-conformal columnar growth [99]. If the material to be deposited does not wet the substrate surface, application of an intermediate buffer layer may be necessary to ensure perfect replication of the substrate pattern [100,101]. Furthermore, in the case of polycrystalline films, the disorder between the different grains in the film may result in a loss of conformity already at low film thicknesses.…”

“…If the nanopatterned substrate surface is crystalline, highly conformal films can also be grown epitaxially, if the lattice constants between film and substrate material are a match (see Figure 3b) [94]. Finally, various layer stacks [69,101,103] and multilayers [27,104] have also been grown on nanopatterned substrate that replicated the substrate topography very well (see Figure 3c). Pattern transfer into polymeric materials is more complex.…”

Metal impurity-assisted formation of nanocone arrays on Si by low energy ion-beam irradiation

“…Moreover, nanostructures with very similar morphology and dimensions can also be produced by plasma-based methods [45,53,54]. Nanocones are not exclusive to silicon: metals [47,48,50], carbon and other carbonaceous materials [46,49] including diamond [55], as well as GaSb [56] have also been reported as surfaces where such structures could be fabricated by ion irradiation. Interestingly, the observations that formation of nanocones on ion-irradiated surface can be aided by co-deposition of impurity atoms were made already in the 1970s [47][48][49].…”

“…In this paper we specifically describe ion-irradiated nanostructured samples that have been comprehensively characterized by structure-sensitive (Scanning Electron Micsoscopy, SEM and Atomic Force microscopy, AFM) and chemical composition-sensitive (X-ray Photoelectron Spectrometry, XPS and Total Reflection X-ray Fluorescence Spectrometry, TXRF) surface characterization techniques in order to better understand the interplay between the chemical composition of these materials and the structure of their surfaces. One of the key questions we asked was whether the silicide formation was indeed the primary driver of the surface self-organization in this case, especially in view of others reporting the same structures forming on diamond and other materials irradiated by low energy ions [40,46,56].…”