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The influence of high magnetic field annealing on the morphology, microstructure, and properties of pulsed-electrodeposited Co-Ni-P films was investigated. The as-deposited film with a rough surface changed into uniform nanocrystalline during the magnetic field annealing process. In particular, the formation of intestine-like appearance with spherical clusters vanishing is favored from a moderate magnetic field strength of 6 T, due to the polarized effects. Meantime, the diffraction peak (111) of α (fcc) phase shifts to the right direction, which is attributed to the fact that more Co atoms from phosphide phase are incorporated into the Ni lattice, in comparison with the case of annealing under 0 T and 12 T magnetic fields. The mechanical and magnetic properties of the films reach relative optimum values at B=6 T. The evolution of magneto-induced modification in the Co-Ni-P morphology, structure, and properties can be explained by the polarized effect and the diffusion-acceleration effect under a high magnetic field. [ABSTRACT FROM AUTHOR]

The effects of silicide formation on the surface structure and magnetic properties of Co thin films on Si (100) were investigated. Annealing temperature significantly changed the formation of silicide. CoSi phase was formed during annealing at 600 °C and 700 °C. CoSi2 phase was formed during annealing at 800 °C. The anisotropy of Co/Si (100) films changed due to the formation of silicide. In addition, both the particle size and the surface roughness increased with the increase of annealing temperature, which led to the increase of coercivity up to 700 °C. However, the better crystallinity HC decreased at 800 °C. [ABSTRACT FROM AUTHOR]

Nanocrystalline Fe 30 Ni 70 (in atomic %) thin films were prepared by molecular-beam-vapor deposition in magnetic fields with different magnetic flux densities. The microstructure evolution of these thin films was studied by atomic force microscopy, transmission electron microscopy, and high resolution transmission electron microscopy; the soft magnetic properties were examined by vibrating sample magnetometer at room temperature. The results show that all our Fe 30 Ni 70 thin films feature an fcc single-phase structure. With increasing magnetic flux density, surface roughness, average particle size and grain size of the thin films decreased, and the short-range ordered clusters (embryos) of thin films increased. Additionally, the magnetic anisotropy in the in-plane and the coercive forces of the thin films gradually reduced with increasing magnetic flux density. [ABSTRACT FROM AUTHOR]

The influence of interdiffusion on the magnetic properties of Co/Si (100) films after thermal annealing in the presence of a strong magnetic field was investigated. The interdiffusion coefficients of films that were annealed at temperatures of 380 °C and 420 °C in the presence of high magnetic fields were not affected. However, the interdiffusion coefficient of films annealed at 400 °C in the presence of a high magnetic field decreased significantly. The change in the interdiffusion coefficient, caused by high magnetic field annealing, increased the content of the magnetic phase. This increase in the magnetic phase improved the saturation magnetization. A new method of high magnetic field annealing is presented that can modulate the diffusion and magnetic properties of thin films. [ABSTRACT FROM AUTHOR]

The effects of high magnetic field annealing on the inter-diffusion behavior of Co/Si (100) films were investigated using diffusion couple technique. Significant Co and Si inter-diffusion was verified by X-ray photoelectron spectroscopy. The inter-diffusion coefficients of thin-film/semiconductor were calculated. Compared to the no-field case, the inter-diffusion coefficients clearly increased when a high magnetic field of 11.5 T was applied at 300 °C, 350 °C, 450 °C and 500 °C. This effect can be attributed to an increase in the chemical potential gradient induced by magnetic free energy in a high magnetic field. For the samples at 400 °C, the inter-diffusion coefficients decreased when a high magnetic field of 11.5 T was applied. The phenomenon may due to the structure transformation caused by a high magnetic field. [ABSTRACT FROM AUTHOR]

The Fe 60 Ni 40 (in atomic %) nanoparticles (NPs) thin films with 90 nm thickness were prepared on 25 and 400 °C quartz substrates by using the molecular beam vapor deposition (MBVD) method under a 6 T high magnetic field (HMF). The effects of a HMF on the structure evolution and properties of Fe–Ni thin films were studied by using X-ray diffraction, atomic force microscopy, transmission electron microscopy, vibrating sample magnetometer and four-point probe method. The results show that the crystallinity of thin films is enhanced by a 6 T HMF, and a 6 T HMF changes phase composition of thin films on 25 °C substrate. It is found that the nanoparticle size decreases; the nanoparticle size distribution becomes narrow, and the root mean square (rms) roughness of thin films decreases under a 6 T HMF relative to that without HMF. These lead to the decrease of coercive force, and the increase of in-plane remanence ratio under a 6 T HMF. [ABSTRACT FROM AUTHOR]

Abstract: The effect of a high magnetic field on phase formation and determination in Ni–Fe film at nanoscale is reported. The bcc structure of the film changed to the coexistence of bcc and fcc phases by increasing the substrate temperature from 25 to 200 to 400 °C without magnetic field. Under a 6 T magnetic field, a coexistence of bcc and fcc phases was formed whatever structures the films prepared without magnetic field are. Furthermore, each nanograin exhibited only a single phase. The effect of high magnetic field indicates that the reduction in the Gibbs free energy (entropy) for the fcc phase by the high magnetic field is larger than that for the bcc phase. Furthermore, the reduction is different for various substrate temperatures. The results indicate that the phase formation is tunable at the nanoscale under high magnetic field. [Copyright &y& Elsevier]

Abstract: The effect of high magnetic fields up to 12T, applied during electrodeposition process, on the morphology of nanocrystalline CoNi films has been investigated. The magneto-induced dramatic modifications in the morphology were observed by using field-emission scanning electronic microscopy and atomic force microscopy. Along with the increase of magnetic flux density (B), the grain size and the surface roughness of the films increased to reach a maximum value at a field of 9T. Meanwhile, higher magnetic flux density could improve cobalt atomic percentage in the film due to the impacts of magnetohydrodynamic effect. However, at a high field of 12T, the paramagnetic force played a predominant role in a decrease of mass transport, resulting in minimum grain size and roughness, even smaller than that of the ordinarily (B=0T) sample. [Copyright &y& Elsevier]

Abstract: The effects of high magnetic field annealing on the interdiffusion of Co/Ni bilayer films were investigated in this paper. A clear CoNi alloying zone can be observed by field emission scanning electron microscopy and energy dispersive spectroscopy, for samples annealed with and without magnetic field. Significant Co and Ni interdiffusion was verified by X-ray photoelectron spectroscopy. Based on the thickness of the diffusion layer, the distribution of atoms and the microstructure of interfacial products, the interdiffusion coefficients of the bilayer diffusion couples were calculated. Compared with the no-field case, the interdiffusion coefficient clearly increased when a high magnetic field of 12T was applied. This effect can be attributed to an increase in the chemical potential gradient induced by magnetic free energy in a high magnetic field. [Copyright &y& Elsevier]