Structural properties of magnetic thin films for data storage (original) (raw)
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Thin Films for Magnetic Recording Tech nology : A Review
2017
Chen et al., "The Effect of Orientation, Grain Size and Polymorphism on Magnetic Properties of Sputtered Co-ReThin Film Media", IEEE Transactions on Mag netics, MAG 17, No. 6, 1981, pp. 3187-3189. Potzlberger, "Magnetron Sputtering of Permalloy for Thin-Film Heads", IEEE Transactions on Magnetics, MAG 20, No. 5 Sep. 1984, pp. 851-853. Treves, "Platinum-Cobalt Films for Digital Mag neto-Optic Recording", Journal of Applied Physics, vol. 46, No. 6, Jun. 1975, pp. 2760-2765. Allyn et al., "Thin-Film Discs: Magnetic, Electrical
Crystalline texture and magnetic anisotropy of Co-P films prepared by chemical deposition
Physics of Metals and Metallography, 2007
Chemically deposited Co-P films with a P concentration of 2.5% have been studied by X-ray diffraction (Bragg geometry), electron microscopy, and magnetometry. The films have been found to represent a fine-grained medium in which the orientation of crystallites depends on the film thickness. At a thickness less than 70 nm, the films have a certain crystalline texture with a preferred orientation of the hexagonal axis c of the crystallites perpendicular to the film plane. With increasing film thickness, the character of the texture changes; the c axes of crystallites lie now predominantly in the film plane. At thicknesses exceeding 500 nm, the texture becomes stronger; the c axes are now distributed in the film plane equiprobably. These results can be used when producing magnetic media for longitudinal and transverse magnetic recording.
Magnetic particulate thin films on bilayer lipid membranes
The Journal of Physical Chemistry, 1989
Cationic magnetic Fe304 particles have been shown to be strongly attracted onto one or both surfaces of glyceryl monooleate (GMO) bilayer lipid membranes (BLMs). The absence of capacitance changes across the GMO BLM during deposition has been interpreted to imply that the Fe304 particles did not penetrate beyond the headgroup region (headgroup distance, dp = 6-8 A; hydrocarbon bilayer distance, dh = 48 A; BLM thickness, db = 26, + dh = 62 * 2 A) of the surfactants constituting the BLM. Incident-angle-dependent reflectance measurements led to a model for the Fe304-particle-coated GMO BLM with the following parameters: refractive index of the magnetic particles, n, = 1.96; thickness of the magnetic particles on the BLM, D, = 55.1 A (0, = d, + dp); center-to-center distance between the magnetic particles, S, = 57.6 A. Fe304 particles attracted to the BLM so strongly that they could not be pulled away by a magnet even as strong as 400 Oe. This strong attraction overcame the electrostatic repulsions between neighboring particles and permitted the coverage of the BLM to the extent that it was tantamount to the formation of a monolayer of particulate film. Formation of a second layer of particulate film was proposed to be precluded by particle-particle replusions that prevailed in the absence of the attractive forces of the BLM. Longitudinal Faraday and Kerr effects as functions of the angle of incident light have been calculated and experimentally determined for GMO BLMs coated on one and both sides of particulate Fe304 thin films. Magnetic domains have been visualized by polarized videomicroscopy of the Kerr rotation.
IEEE Transactions on Magnetics, 2000
The FePt:C films with different volume fractions of carbon were epitaxially grown on the CrRu(200) underlayer with Pt and MgO intermediate layers. The magnetic properties and microstructure of these FePt:C films were investigated. The FePt:C films grown on Pt intermediate layer consisted of a continuous layer of FePt, with overlying granular FePt grains. The FePt:C films grown on MgO intermediate layer consisted of a granular FePt:C layer with overlying granular grains. The formation of the overlying granular FePt grains was attributed to carbon diffusion to the surface, which resulted in the second nucleation of FePt. The different interface energy and surface energy of FePt on Pt and MgO intermediate layers caused the formation of initial continuous FePt layer on Pt intermediate layer and initial granular FePt layers on MgO intermediate layer. The out-of-plane coercivity measured at room temperature increased from 10.2 to 19 kOe when C concentrations increased from 0 to 15%. Further increasing the C contents to 20% and 25% caused the decrease of coercivity to 17.2 and 14.8 kOe, respectively. The coercivity of the exchange coupling assisted FePt:C perpendicular media was indeed substantially reduced.
Applied Surface Science, 2012
Structure and morphology modifications Magnetic field effect pH effect Electrolyte temperature a b s t r a c t Cobalt films were deposited by use of the electrochemical process from a cobalt (II) sulfate solution on a titanium electrode and characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The experiments at electrolyte temperature of 50 • C were performed which is commonly used in the industrial process. The effects of pH and low uniform magnetic field up to 1 T on structure and morphology changes were investigated. The detected phase composition indicates the presence of both phases: hexagonal centered packed and face centered cubic independent on the pH value and the applied magnetic field amplitude. Calculation of the orientation index of Co phase shows the preferential orientation in the films obtained at higher pH. SEM micro-imagines have shown the nucleus shape transition from coarse-grained to needle-shaped dependent on the application of B-field as well as on the pH variation in the case of higher pH level. Co-films obtained from the electrolyte of low pH were characterized by the fine-grained morphology which was not modified by the influence of magnetic field. AFM images proved the effect on roughness of the Co-films which is closely related with the obtained morphology.
Microstructural and crystallographic aspects of thin film recording media
IEEE Transactions on Magnetics, 2000
Various aspects of the structure of thin film longitudinal recording media are presented and discussed. In particular we discuss the role that the various layers of thin film media play in controlling the microstructure and magnetic properties of the magnetic layer. These include the grain size of the films, the texture of the films, the role of the intermediate layer and the role of chemical segregation.