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Full-Text Articles in Physics
Nanocomposite Copt:C Films For Extremely High-Density Recording, M. Yu, Yi Liu, A. Moser, D. Weller, David J. Sellmyer
Nanocomposite Copt:C Films For Extremely High-Density Recording, M. Yu, Yi Liu, A. Moser, D. Weller, David J. Sellmyer
David Sellmyer Publications
Nanocomposite CoPt:C films were investigated as potential media for extremely high-density recording. An annealing temperature of over 600 °C is necessary to form nanocomposite CoPt:C films consisting of C matrix and fct CoPt nanocrystallites with grain sizes of 8–20 nm and coercivities of 3–12 kOe. Coercivity and grain size increase with increasing annealing temperature and decreasing C concentration and they are insensitive to film thickness. The average activation volumes are about 0.9×10-18 cm3. The properties of these nanocomposite CoPt:C films can be tailored to satisfy the thermal stability, coercivity, and media noise requirements for extremely high-density recording.
Structural And Magnetic Properties Of Fept:Sio2 Granular Thin Films, C.P. Luo, David J. Sellmyer
Structural And Magnetic Properties Of Fept:Sio2 Granular Thin Films, C.P. Luo, David J. Sellmyer
David Sellmyer Publications
Nanocomposite FePt:SiO2 films have been fabricated by annealing the as-deposited FePt/SiO2 multilayers at temperatures from 450 to 650 °C. These films consist of high-anisotropy tetragonal L10 FePt particles embedded in a SiO2 matrix. The structural and magnetic properties of these films were investigated. We have found that coercivity and grain size are highly dependent on the annealing temperature and SiO2 concentration. Films with coercivities in the range from 2 to 8 kOe and grain sizes of 10 nm or less were obtained. These films have considerable potential as high-density magnetic recording media.
Correlation Of Co(Llo)/Cr(002) Texture And Magnetic Properties In Cocrtapt Granular Films, Z.S. Shan, C.P. Luo, M. Azarisooreh, K. Honardoost, M. Russak, Yi Liu, J. Ping Liu, David J. Sellmyer
Correlation Of Co(Llo)/Cr(002) Texture And Magnetic Properties In Cocrtapt Granular Films, Z.S. Shan, C.P. Luo, M. Azarisooreh, K. Honardoost, M. Russak, Yi Liu, J. Ping Liu, David J. Sellmyer
David Sellmyer Publications
Studies of the effects of substrate temperature T, on the evolution of CO( 1 10)/Cr(002) texture, magnetic and physical grain size, intergrain-interaction, anisotropy, orientation ratio of remanence and coercivity were investigated experimentally. It is found that the hcp- Co(l10)hcc-Cr(002) texture is improved with increasing T, from 27OC to 265°C. The intergrain-interaction, magnetic and physical grain size decrease with increasing Ts and reach their minima at T,- 265°C where the magnetic grain size is close to the physical grain size. The correlation between the film microstructure and magnetic properties is studied systematically.
High Energy Products In Exchange-Coupled Nanocomposite Films, J. Ping Liu, Yi Liu, Ralph Skomski, David J. Sellmyer
High Energy Products In Exchange-Coupled Nanocomposite Films, J. Ping Liu, Yi Liu, Ralph Skomski, David J. Sellmyer
David Sellmyer Publications
Several systems of nanocomposite thin films have been prepared by plasma sputtering and heat treatment. By choosing suitable multilayer structures of the as-deposited films and subsequent heat-treatment processes, the nanostrnctures of the films have been tailored. The thermal processing is the key to control the morphology. Appropriate heat-treatment processes have been found for the systems studied, which result in the desired nanostructures. For the first time a nearly ideal nanostructure with the soft-phase grains embedded homogeneously in the hard phase gralns has been obtained for the FePt-Fei.,Pt,(x-0.3) system. Effective intergrain exchange coupling has been realized. As a consequence, high energy …
Quasicoherent Nucleation Mode In Two-Phase Nanomagnets, Ralph Skomski, J. Ping Liu, David J. Sellmyer
Quasicoherent Nucleation Mode In Two-Phase Nanomagnets, Ralph Skomski, J. Ping Liu, David J. Sellmyer
David Sellmyer Publications
Magnetization processes in advanced magnetic nanostructures are investigated. For the case of spherical soft or semihard grains surrounded by a very hard matrix a bulging nucleation mode is discovered. The bulging mode exhibits the radial angular symmetry of the coherent mode, but it is incoherent due to its radial variation. The radial dependence of the bulging mode is obtained by solving a spherical Bessel equation which is subject to appropriate boundary conditions. In contrast to the coherent mode, the bulging mode yields a nucleationfield coercivity which depends on the exchange stiffness and on the size of the grain. There is …
Structural And Magnetic Properties Of Nanocomposite Co:C Films, M. Yu, Yi Liu, David J. Sellmyer
Structural And Magnetic Properties Of Nanocomposite Co:C Films, M. Yu, Yi Liu, David J. Sellmyer
David Sellmyer Publications
The structural and magnetic properties of Co:C nanocomposite films at room temperature were investigated as functions of annealing temperature, Co concentration, and film thickness. The as-deposited films, which were cosputtered from Co and C onto water-cooled glass substrates, are nonmagnetic amorphous Co–C alloys. Hexagonal-close-packed (hcp) Co grains are formed in 100 nm films annealed at 300 °C and most Co takes this structure when annealed at higher temperatures. The sizes of the Co grains range from 10 to 25 nm, with larger grain size resulting from higher annealing temperature and higher Co concentration. With the increase of annealing temperature and …
Effects Of Layer Thickness On Orientation Distribution And Magnetic Properties Of Cocrta/Cr Films, Z.S. Shan, H. Zeng, C.X. Zhu, M. Azarisooreh, K. Honardoost
Effects Of Layer Thickness On Orientation Distribution And Magnetic Properties Of Cocrta/Cr Films, Z.S. Shan, H. Zeng, C.X. Zhu, M. Azarisooreh, K. Honardoost
David Sellmyer Publications
Evolution of orientation distribution of Co(110) crystal planes was determined by x-ray rocking curves. It has been found that: (i) The full-width at half maximum W of the Co(110) rocking curve decreases with both increasing Cr underlayer thickness dcr, and increasing CoCrTa magnetic layer thickness dco, especially in the thin layer regime. (ii) For the thin dcoregime, the interlayer diffusion between the Cr underlayer and the magnetic layer affects the rocking curves and magnetic properties significantly. (iii) Film magnetic properties, e.g., a significant jump in coercivity with increasing magnetic layer thickness in the thin …
Magnetic Hardening In SmcoX–Co Multilayers And Nanocomposites, J. Ping Liu, Yi Liu, Ralph Skomski, David J. Sellmyer
Magnetic Hardening In SmcoX–Co Multilayers And Nanocomposites, J. Ping Liu, Yi Liu, Ralph Skomski, David J. Sellmyer
David Sellmyer Publications
SmCox–Co (x = 3.5, 4, and 5) nanostructured multilayers have been prepared by dc and rf sputtering. Magnetic hardening has been found in the as-deposited thin films. The effects of the Co and hard-phase layer thicknesses and the effect of the Cr underlayer have been studied. Further magnetic hardening has been achieved by heat treating the samples. A remarkable increase of the coercivity has been obtained in the nanocomposite films, with coercive force up to 40 kOe. Transmission electron microscopy, atomic force microscopy, and magnetic force microscopy observations have been performed to understand the nanostructure and the domain …
Effects Of Layer Thickness On Orientation Distribution And Magnetic Properties Of Cocrta/Cr Films, Z. S. Shan, H. Zeng, C. X. Zhu, M. Azarisooreh, K. Honardoost, Yi Liu, David J. Sellmyer
Effects Of Layer Thickness On Orientation Distribution And Magnetic Properties Of Cocrta/Cr Films, Z. S. Shan, H. Zeng, C. X. Zhu, M. Azarisooreh, K. Honardoost, Yi Liu, David J. Sellmyer
David Sellmyer Publications
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