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This paper considered the transient drainage of a linearly viscous magnetohydrodynamic (MHD) fluid down a vertical flat slippery belt. An inhomogeneous partial differential equation with an inhomogeneous boundary condition was developed. Exact solutions for the velocity distribution, flow rate, surface profile, and variable thickness were then computed. The effect of MHD and the slip parameter on the velocity, flow rate, and surface profile were then considered. The effect of the magnetic field on the derived flow properties was discussed and represented graphically. It was determined that the absence of the magnetic field and the assumption of no-slip boundary conditions reduced the problem to the well-known Jeffreys problem. Key words: thin film flow, linearly viscous fluid model, MHD, exact solutions, transient drainage, slippery belt. Nous etudions ici le drainage transitoire d'un fluide MHD a viscosite lineaire, descendant sur une courroie verticale, plate et glissante. Afin de le decrire, nous developpons une equation differentielle aux derivees partielles inhomogene avec une condition limite inhomogene. Nous calculons des solutions exactes pour la distribution de vitesse, le taux d'ecoulement, le profil de surface et l'epaisseur variable. Nous considerons alors l'effet du caractere MHD et du parametre de glissement sur la vitesse, le taux d'ecoulement et le profil de surface. Nous discutons l'effet d'un champ magnetique sur les proprietes d'ecoulement et representons cet effet graphiquement. Nous determinons ensuite, qu'en l'absence de champ magnetique et sans condition limite de glissement, le probleme se reduit au probleme bien connu de Jeffreys. [Traduit par la Redaction] Mots-cles: ecoulement d'un film mince, modele de fluide a viscosite lineaire, MHD, solutions exactes, drainage transitoire, courroie glissante. PACS Nos.: 01, 47, 02.30., 1. Introduction The flow of fluid in the form of thin layers is called thin-film flow. A thin film consists of an expanse of liquid bounded by a solid body [...]

Scratch-related magnetic signal degradation can occur during magnetic storage hard disk drive operations when the read-write heads contact the spinning multilayer disks. To investigate this phenomenon, controlled nanoscratch experiments were performed on perpendicular magnetic recording media using various indenters of different radii of curvature. Various loading conditions were used to cause permanent scratches that were measured using atomic force microscopy. The nanoscratch experiments were simulated using finite element analysis (FEA) that included the detailed nanometer scale thin-film multilayer mechanical properties. The permanently deformed field in the subsurface magnetic recording layer was extracted from the FEA results. The residual scratch widths measured on the surface of the magnetic storage disk were directly compared with the residual subsurface widths of the region on the magnetic recording layer, where extensive permanent lateral deformation was present. It was found that the subsurface widths of the deformed regions were significantly larger than the surface scratch widths. Thus, subsurface thin-film layers, such as the magnetic recording layer, could be damaged without observable damage to the protective top surface carbon overcoat. The exact location and extent of damage to the magnetic recording layer depends on the scratch load, size of scratch tip, and the friction at the interface. Such permanent deformation in magnetic recording layer could lead to demagnetization, which has been reported in the literature. [DOI: 10.l115/1.4000848] Keywords: magnetic storage, nanoscratch, finite element analysis, demagnetization, multilayer thin-films

Magneto-dielectric substrates with thin magnetic films show great potential in realizing electrically small tunable antennas with enhanced bandwidth, improved directivity, and high efficiency. This communication introduces self-biased NiCo-ferrite magnetic films as a practical mean to tune a patch antenna by loading single layer and multilayer self-biased ferrite films. The central resonant frequency of the unloaded patch antenna is measured at 2.1 GHz with a bandwidth of 18 MHz. However, with ferrite loading of the alumina substrate, this frequency is shown to be tunable within a range of 12 MHz--40 MHz, and the antenna efficiency is increased from 41% of the non-magnetic antenna to 56%, 65%, and 74% for the three magnetic antennas. The omnidirectional radiation pattern is significantly enhanced with the -5 dBic gain beamwidth increased from 140[degrees] to 155[degrees], 156[degrees] and 160[degrees], respectively for the three ferrite loaded antennas. In addition, the gains of the three magnetic antennas are enhanced by 0.32, 0.77, and 1.1 dB, respectively, over the unloaded antenna. Index Terms--Magnetic films, self-biased films, tunable magnetic antennas.

Dynamic behavior of magnetic thin film actuators is investigated in detail and applied to various laser scanning applications. Magnetic hysteresis effects are incorporated into the model developed in the prior work, which assumes linear magnetization as a function of magnetic field and is based on the distributed point-by-point calculation of the magnetostatic moments and forces across the film surface. A simple functional form is used to model the major B-H loop of ferromagnetic films. The model is validated with permalloy (Ni-Fe) plated polymer actuators. The actuators are excited using an external electro-coil and the structures deflect due to magnetic anisotropy torque. The ac deflection of the actuators is modeled by calculating the point-by-point moments on the magnetic film and the solution can handle nonuniform external field and unsaturated magnetic film cases. A 25[degrees] optical scan angle is demonstrated for laser scanning display and imaging applications with a nonoptimum coil. Scaling the model to MEMS devices is also discussed. Index Terms--B-H loop modeling, magnetic actuators, magnetic hysteresis, optical scanning, permalloy, scanner.

Problem statement: The electroplating technique is especially interesting due to its low cost, high throughput and high quality of deposit. Magnetic thin films are extensively used in various electronic devices including high density recording media and Micro Electro Mechanical (MEMS) devices. So we examined FePt films and give good magnetic properties. Approach: The Pt-rich FePt alloys were electrodeposited galvanostatically by various temperature baths. Results: The elemental percentage of Pt in the film was very high determined by X-ray spectroscopy. Surface characterization was carried out by using X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM).The magnetic properties determined by Vibrating sample magnetometer. Hardness and adhesion of the films were also discussed. Conclusion/Recommendation: The films were soft magnetic character of lower temperature bath and become a hard magnetic character of higher temperature bath. Therefore this magnetic films could be an important material for incorporate in Micro electro mechanical devices. Key words: FePt, electrodeposition, magnetic film, magnetic properties, INTRODUCTION With the progress in the field of Micro Electro Mechanical System (MEMS) technologies (1), (2), (3), (4), (5) there has been growing interest in developing electroplated, nanostructured soft and [...]

The characteristics of the electromagnetic noise suppression have evaluated using magnetic nanowire-filled composite film on a microstrip line in the broadband radio-frequency range from 0.5 to 20 GHz. The ferromagnetic resonance frequency and the relative complex permeability with the change of aspect ratio were calculated by Kittel's and Landau-Lifshitz-Gilbert equations. The FMR frequency is gradually increased with the increment of aspect ratio (up to 50) of magnetic nanowire. When the magnetic nanowires were mixed with various aspect ratio in composite, the FMR frequency exhibited the broadband frequency regions with 10-28 GHz, 5-14 GHz, 2.5-7 GHz, and 1-2.7 GHz for the change of magnetizations (4[pi][M.sub.s] : 20, 10, 5, and 2 kG), respectively. Using the calculated FMR frequency profile, the power losses were obtained in broadband frequency region. The transmission power absorption of the composite film on microstrip line was simulated using a 3-D FEM HFSS simulation program. The microstrip line model was composed of Cu conductor line and grounded dielectric substrates, which was designed by IEC standard (IEC 62333-2). The conduction electromagnetic noise was suppressed by the various aspect ratios of the magnetic nanowire-filled composite films in broadband frequency region. Index Terms--Ferromagnetic resonance, magnetic composite sheet, microstrip line, noise suppression, power loss.

The effect of Pt doping on the structure, magnetic and magneto-optical properties of [FeRh.sub.100-x][Pt.sub.x] thin films with 0 [less than or equal to] X [less than or equal to] 25 was investigated in present paper. Ordered [alpha]' FeRh phase is formed in the thin films with X up to 15 and ordered [Ll.sub.o] FePt phase shows up when X is larger than 10. The first-order magnetic phase transition occurs when X is less than 15. The transition temperature increases with increasing Pt content while the Curie temperature decreases with increasing Pt content in the samples. The effect of external magnetic field shows that an external applied magnetic field will stabilize the ferromagnetic phase and consequently decrease the transition temperature. But the effect of external applied magnetic field on the AFM/FM phase transition is restrained by the addition of Pt. In addition, a (negative) maximum peak and a small shoulder peak were observed at photon energy of around 3.8 eV and 4.7 eV, respectively, in the polar magneto-optical Kerr spectra. Index Terms--FeRh, thin film, magnetic transition, polar magneto-optical Kerr effect.

The effect of carbon mixing on the perpendicular magnetization of magnetron sputtered FePt thin films on our newly developed underlayer of Pt/MgO(p) composite thin-film was studied using magnetic property measurement and X-ray diffraction, and TEM microscopy. Micromagnetic simulation was carried out to study the effect of texture on the perpendicular coercivity. Unlike a general expectation, the mixing of FePt with carbon led to a significant enhancement in the perpendicular magnetization. The maximum enhancement of perpendicular magnetization was observed at about 22 vol.% of carbon, where carbon amorphous film started to completely enclose the individual FePt grains. This was because the epitaxial growth and thus perpendicular texture of ordered FePt grains were maximized in the isolated grain structure due to a maximum relaxation of coherency strain for epitaxial growth. The simulation showed that the enhancement of perpendicular texture can largely increase the perpendicular coercivity of FePt:C thin film. Index Terms--Epitaxial growth, FePt:C magnetic thin films, perpendicular magnetization, texture.

CoPt and CoPt/Au films prepared by magnetron sputtering were studied in this paper. The films were deposited at room temperature followed by a post annealing at temperatures ([T.sub.a]) from 400[degrees]C to 800[degrees]C. Ordering of the CoPt and CoPt/Au films occurred at [T.sub.a] = 600[degrees]C and 500[degrees]C, respectively, which results in magnetic hardening. With the increase of [T.sub.a] up to 700[degrees]C, coercivity of the both films increased to a maximum value of about 12 kOe. As [T.sub.a] reached 800[degrees] C, a drastic magnetic softening occurs in both samples; meanwhile, the diffraction data indicate a corresponding phase change from tetragonal to cubic. Scanning electron microscopy results revealed an intensive grain growth from 70 nm at 700[degrees]C to 160 nm at 800[degrees]C for CoPt/glass film and from 110 nm at 700[degrees]C to 250 nm at 800[degrees]C for CoPf/Au/glass sample. The relation between the abnormal phase change and intensive grain growth indicates that the formation of the cubic phase is driven by large biaxial tensile stress. Further investigations support this explanation and reveal that the cubic phase may be chemically ordered. Index Terms--CoPt, magnetic softening, phase transformation, thin films.

We report the magneto-transport properties of [La.sub.0.7][Ca.sub.0.3-x][Sr.sub.x]Mn[O.sub.3] (x = 0, 0.075, 0.1, 0.125, 0.15, 0.3) thin films on (100) LaAl[O.sub.3] substrates prepared by pulsed electron-beam deposition (PED). With increasing x from 0 to 0.3, both Curie temperature ([T.sub.C]) and metal-insulator transition temperature ([T.sub.MI]) of the films were increased from 206 and 212 K to 339 and 366 K, respectively. Except x = 0.125 film, with increasing x, all other LCSMO films showed a tendency of gradual decrease in the maximum MR ratios ([MR.sub.MAX]) at increased maximum MR temperature ([T.sub.MAX],) values. The film of x = 0.125 exhibited extraordinary high [MR.sub.MAX] value of 16% at 306 K. After post-annealing in a pure oxygen atmosphere at 900[degrees]C, this film showed more enhanced [MR.sub.MAX] of 18% at 325 K. Index Terms--Colossal magnetoresistance (CMR), perovskite manganites films, pulsed electron-beam deposition (PED).

NiFe epitaxial thin films were prepared on MgO(100) and SrTi[O.sub.3](100) single-crystal substrates by UHV-molecular beam epitaxy. The effects of substrate material and substrate temperature on the structure and the magnetic properties were investigated. In the early stage of NiFe film growth on MgO(100) substrate, formation of NiFe(11[bar.2]0) epitaxial film with hcp structure is observed by in-situ RHEED. The metastable hcp-NiFe phase is presumably favored to relax the strain caused by a lattice mismatch at the NiFe/MgO(100) interface. With increasing the film thickness, fcc-NiFe(100) phase appears and the RHEED intensity from the fcc-phase increases. On the contrary, a high-quality fcc-NiFe(100) single-crystal film epitaxially grows on an SrTi[O.sub.3](100) substrate. The magnetic properties of the NiFe epitaxial thin films grown on both the MgO(100) and the SrTi[O.sub.3](100) substrates are influenced by the magnetocrystalline anisotropy of fcc-NiFe crystal and the shape anisotropy caused by the surface undulations. Index Terms--Epitaxial growth, MgO(100), NiFe thin film, SrTi[O.sub.3](100).

A monolayer of [L1.sub.0] FePt nanoparticles was fabricated on a polymer film by introducing a Au seed layer prior to the Fe-Pt deposition on the polyimide film. The particle size distribution was tightened from 5.1 [+ or -] 1.8 nm to 3.8 [+ or -] 1.1 nm by introducing the Au seeds to induce a preferential nucleation of the deposited metal on the preexisting Au particles. Deposition and annealing was repeated so that well-separated hard magnetic nanoparticles with several nanometers in diameter were achieved in a monolayer configuration. The method can be easily extended to a larger area as well as to other alloy systems to create a monolayer of nanoisland structures on a polymer film. Index Terms--Ferromagnetic materials, magnetic recording, polyimide films, quantum dots.

Room temperature diluted ferromagnetic semiconductor is a very promising candidate for spintronics applications. In this work, we present the cobalt ion implanted ZnO epitaxial thin film under controlled annealing temperature to investigate the origin of ferromagnetism in this system. For the as-implanted sample a metallic cobalt cluster was observed. After annealing at 700[degrees]C, the Co atoms were to substitute the Zn sites of the ZnO matrix and exhibited a spontaneous room temperature ferromagnetism. However the XMCD measurements on the annealed samples show the cobalt element is almost paramagnetism at 26 K. The result might indicate oxygen vacancies caused ferromagnetism of intrinsic dilute magnetic semiconductors in the sample of the Co-implanted ZnO. Index Terms--Co-doped ZnO, magnetic circular dichroism (XMCD), magnetic semiconductors.

We report on the magnetoresistance (MR) properties of [[Co(tCo)/Ag 1.5 nm].sub.20] multilayer and alloy films grown with the pulse electrochemical deposition on a polyamide substrate (1 [cm.sup.2]). The induced uniaxial magnetic anisotropy was observed due to the effect of strain in all the multilayer films. The multilayer [[Co 1.5 nm/Ag 1.5 nm].sub.20] showed a minimum hysteresis loss. The maximum MR ratio for Co/Ag was 9.2% at 1 kOe. A remarkable difference of magnetic field dependence of the magnetoresistance ratio was observed, corresponding to the orientation of magnetization curves. Index Terms--Anisotropy, Co/Ag, magnetoresistance, multilayer, pulse electrodeposition.

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. Index Terms--FePt, high coercivity, microstructure, perpendicular media.

In this paper, the problem of writability in bit-patterned media (BPM) for high areal density will be discussed. A new film structure is proposed, made of a composite in-plane and perpendicular anisotropy layers to improve writability and reduce the time of magnetization switching in BPM. To demonstrate the efficiency of an in-plane anisotropy layer in assisting the switching of the magnetization of the high perpendicular anisotropy recording layer, we use micromagnetic simulation to study magnetization reversals in BPM for 5 Tb/[in.sup.2]. Experiments have been carried out on patterned arrays of 60-nm-size dots made of [[Co(0.3 nm)/Pd(0.8 nm)].sub.x15] multilayer and [Co(2 nm)/[Co(0.3 nm)/Pd(0.8 nm)].sub.x15] composite structure. The mean switching field calculated from remanence magnetization curves shows a reduction of more than 50% from its initial value by adding a 2-nm-thick Co bottom layer with in-plane anisotropy. No difference in switching field distribution was observed in the two structures studied, indicating the merit of assisting the switching of high anisotropy patterned media by exchange coupling to an in-plane anisotropy layer. Index Terms--Bit-patterned media, perpendicular magnetic recording, switching field distribution.

Perfluoropolyether lubricant films on magnetic disks were observed by means of atomic force microscopy (AFM) with a fluoride-coated probe. The lubricant films could be observed directly because the adhesion force was decreased by the anti-wetting effect of the fluoride coating on the probes. We compared the molecular conformation of Z-dol (Mw: 2000, 3000, 6000, 8000) with that of Z-tetraol. Thus, we found that the film coverage of a lubricant with high molecular weight exhibited varying (i.e., higher and lower) step heights of the lubricant film boundary. The Z-tetraol film exhibited higher coverage and the higher step height as compared to Z-dol2000. To further study the step height measured by means of atomic force microscopy, we compared the step height with the shoulder height of the spreading profiles of the films. The step heights were almost equal to the shoulder height. We observed the lubricant film after shearing by using contact scanning mode atomic force microscopy. The coverage of the sheared lubricant film increased higher than the initial coverage before shearing. Subsequently, the lubricant molecular conformation was varied due to the shearing, and the coverage was increased. Index Terms--Atomic force microscope, lubricant, magnetic disk, perfluoropolyether.

Thermally assisted magnetic recording (TAMR) is one of the novel technologies that are employed for achieving magnetic recording densities higher than 1 Tb/[in.sup.2]. With regard to this novel technology, it has been suggested that there exists a critical head-disk interface (HDI) issue associated with the use of ultrathin liquid lubricant films on the disk surface. This problem is attributed to the fact that these films are heated to high temperatures by using laser beams in order to reduce magnetic coercivity. In this study, a fundamental research on the lubricant depletion caused due to laser heating in TAMR systems was conducted. That is, the effect of lubricant film materials on lubricant depletion was investigated. In this experimental study, four types of lubricant film materials--Zdol2000, Zdol4000, Ztetraol2000, and A20H2000--were used, and the differences in the characteristics of lubricant depletion for each tested lubricant film were investigated. The effect of the molecular weight as well as the end group of the lubricant on the lubricant depletion was discussed and clarified by analyzing the obtained experimental results. In addition, it was found that the depletion characteristics of ultrathin liquid lubricant films could be explained by using experimental results obtained from the thermogravimetric analysis for each bulk lubricant material. Index Terms--Hard disk drives, laser heating, lubricant depletion, perfluoropolyether lubricant film, thermally assisted magnetic recording systems, thermogravimetric analysis (TGA).

For vapor deposited FePt to be realized as a magnetic recording medium, a basic understanding of the fundamental materials processes in chemical ordering and their interactions with sputter deposition is required. For such applications, a magnetically decoupled nanostructure is necessary as used for longitudinal and perpendicular schemes. The elevated temperatures required for FePt chemical ordering is a major paradigm shift from conventional fabrication. With an understanding of the role of individual materials processes involved with chemical ordering, their implications on physical vapor deposition or other manufacturing systems can be addressed. The feasibility of such processing is shown here with examples of FePt + carbon and FeCuPt + Si[O.sub.2] deposited at elevated temperature. Index Terms--Magnetic anisotropy, magnetic disk recording, magnetic films, sputtering.

In this paper a new model for orthogonal fluxgate is presented. A first attempt to explain the working principle of the orthogonal fluxgates was done in the 1970's. We show that this model does not work well on recently developed orthogonal fluxgate sensors with thin-film core on microwire. A new more accurate two-domain model based both on domain wall motion and magnetization rotation is proposed. We show that the new model better explains the observed properties of thin-film orthogonal fluxgate. Index Terms--Magnetic field measurement, model, orthogonal fluxgate, two-domain.

A linear magneto-impedance (MI) sensor integrated into a FePt thin film bias magnet which has in-plane isotropic magnetic property was investigated. The maximal bias field of 13.1 Oe was obtained after magnetizing a 1.3-[micro]m thick FePt film in longitudinal direction of the sensor element. The bias field changed with the magnetizing angle. By controlling the angle in the magnetizing direction of the bias magnet and sensing direction, it was shown to be able to adjust the effective bias field after fabrication of the sensor element. Index Terms--Bias field, magnetizing angle, magneto-impedance (MI), thin film magnet.

To guarantee a successful fabrication of magnetic micro devices, attaining the desired properties of magnetic thin- films is a precondition. This is particularly true for anisotropic magnetic films. This paper presents the development and fabrication of a micro hysteresis sensor chip consisting of two independent sensors oriented perpendicular to each other. Such an approach allows measuring the properties of anisotropic magnetic thin-films along the two desired axes. The paper describes design, fabrication, and evaluation of the micro hysteresis sensor. Index Terms--BH-loop, magnetic MEMS, micro hysteresis sensor, thin-film technology.

Magnetic thin films have been obtained by radio-frequency (RF) sputtering on [Si.sub.3][N.sub.4] substrates from a [Fe.sub.78][B.sub.13][Si.sub.9] target. The samples, with thickness t varying from 25 to 300 nm, are amorphous; crystalline fraction develops only for t [greater than or equal to] 300 nm. Static hysteresis loops have been measured at room temperature by means of an alternating gradient magnetometer. Samples-having t > 80 nm display a two-slope hysteresis loops: first steep magnetization jump followed by a linear behavior between remanence and saturation revealing the occurrence of a spin-reorientation transition (SRT). The magnetic field [H.sub.K] at which the saturation is reached is connected with the perpendicular anisotropy. Magnetic force microscopy has been performed on all samples, indicating that for t [less than or equal to] 80 nm the magnetization lies in the film plane, while for larger thickness, it is oriented perpendicularly to the film plane. In this work, SRT has been studied as a function of sample thickness and perpendicular anisotropy. In particular, the effect of furnace annealing on the transition from in-plane to out-of-plane configuration will be studied in details. Index Terms--Magnetic films, magnetic force microscopy, magnetization processes.

[Al.sub.2][O.sub.3] films made with atomic layer deposition (ALD) have been developed for use as isolation layers in CPP tunneling magnetoresistive readers. A low-temperature deposition process was developed to permit integration with a self-aligned patterning scheme. The resulting films show excellent thickness uniformity (< 2% within-wafer), leakage current density ([J.sub.leak] < 1 x [10.sup.-8] A][cm.sup.2]) and breakdown properties ([F.sub.bd] > 9 MV/cm). TEMs of sub-100 nm TMR readers fabricated using these processes show > 95% conformality on junction sidewalls, indicating nonselective growth of ALD [Al.sub.2][O.sub.3] on the various stack and bottom shield surfaces. Permanent magnets with well-controlled junction grain structure and coercivities in excess of 2500 Oe have been deposited with existing processes. FEM modeling shows the effective stabilizing field from the magnets at the junction edge scales inversely with ALD layer thickness, in agreement with device-level free layer stability metrics showing improvements at lower ALD thicknesses. As the conformal ALD layer thickness is easily tuned, this technology provides flexibility in trading off reader amplitude and stability that should support scaling of the abutted TMR design out to 1 Tb/[in.sub.2] and beyond. Index Terms--Atomic layer deposition, isolation, permanent magnet, reader, tunneling magnetoresistance.

Sm[Co.sub.5] thin film has been considered as one of several promising candidates for extremely high areal density recording media because of the demand of media with extremely small but thermally stable grains. In this paper, Sm[(Co, Cu).sub.5] films with perpendicular anisotropy were successfully fabricated by dc sputtering with relatively small grain size. Zero in-plane coercivity and 11 kOe out-of-plane coercivity were obtained on Ta(3 nm)/Sm-Co-Cu(10 nm)/Ru(20 nm)/Ta(4.2 nm) thin films. Effects of deposition temperature, film composition, and film thickness on the magnetic properties of SmCoCu films were investigated and reported. Index Terms--Energy assisted magnetic recording, heat assisted magnetic recording, magnetic media, perpendicular anisotropy, Ru underlayer, Sm[(Co, Cu).sub.5], Sm[Co.sub.5].

Addition of Cu into [L1.sub.0]-ordered FePt alloy thin films with (001) preferential orientation results in the change of Curie temperature. Due to these aspects, the films have potential for next-generation high density perpendicular magnetic recording media, especially, heat-assisted magnetic recording (HAMR) media. FePt(Cu) films were fabricated by annealing Pt(Cu)/Fe bilayers prepared by facing targets sputtering. Their magnetic properties were investigated from room temperature to 300 [degrees]C. As a result, it is possible to control Curie temperature from 150 [degrees]C to 250 [degrees]C by changing the amount of Cu in FePt(Cu) films. In addition, we discuss required characteristics of medium for HAMR and mention that the [Fe.sub.55.3] [Pt.sub.37.5] [(Cu).sub.7.2] film exhibited favorable characteristics for the HAMR medium. Index Terms--Curie temperature, FePt, FePt(Cu), heat-assisted magnetic recording.

FePt thin films are deposited on SrTi[O.sub.3], MgO, and a 2 nm-[O.sub.x] underlayer on an Si substrate at room temperature and then annealed at elevated temperatures. Studies of the [L1.sub.0] ordering process in each case show that the ordering temperature for the FePt film on the nonepitaxial Si/Fe[O.sub.x] substrate is ~150 [degrees]C lower than the epitaxial FePt films deposited on MgO and SrTi[O.sub.3] substrates. We argue that internal stresses arising from lattice defects and a recrystallizing process as well as thermal strain from differences in thermal expansion between substrate and film are responsible for the differences in ordering kinetics from the A1 to [L1.sub.0] phase of FePt on the various substrates. Index Terms--Epitaxial growth, FePt, nonepitaxial growth, ordering kinetics.

This paper explores [(FePt).sub.100-x-][(MgO).sub.x] films with x = 0 - 6.13, deposited on an MgO underlayer at elevated temperatures by sputtering. The films exhibit good (001) texture and perpendicular anisotropy. The effects of adding MgO are summarized as follows: 1) the (001) alignment is degraded, increasing the in-plane squareness ratio ([S.sub./]/); 2) a linear dilution of magnetization at an applied field of 6 Tesla was observed; and 3) a critical MgO content of 1 vol. % was found for chemical ordering, microstructure, and anisotropic field ([H.sub.k]). Below this critical content, the ordering of FePt and its microstructure remain similar to those with x = 0 but with a markedly enhanced [H.sub.k]. As x exceeded 1 vol. %, the ordering declined linearly with increasing MgO content. Additionally, a well-defined granular structure was formed and [H.sub.k] was reduced. The decrease in the lattice constant along the c-axis as x increased between 0 and 1 vol. % reveals that the enhancement of [H.sub.k] is related to the relaxation of the residual strain/stress that originates from the ordering transformation of FePt. Adding the proper amount of MgO improved the magnetic properties of (001)-textured FePt. Index Terms--[L1.sub.0] FePt, MgO addition, MgO underlayer, perpendicular anisotropy.

This paper presents the comparison between two different numerical schemes for the analysis of switching phenomena in magnetic thin films. The first one is based on the finite-difference computation of the Landau--Lifshitz equation and on the magnetostatic field evaluation by fast Fourier transforms. The second one handles the spatial discretization of the Landau--Lifshitz equation by the edge finite-element method and solves the Poisson equation for the magnetostatic field with a hybrid finite element/boundary element technique. Index Terms--Finite-difference methods, finite-element methods, Landau--Lifshitz equation, magnetization reversal, thin films.

This paper reports on the thermal field annealing effect of microwave permeabilities in CoFeHfO thin films. For the high resistive optimized [Co.sub.19][Fe.sub.53][Hf.sub.8][O.sub.20] thin films annealed at 150[degrees]C, apart from excellent magnetic performance very low Gilbert damping constants ([alpha] < 0.017) are obtained up to film thickness of 437 nm. The results are interpreted in terms of changes in microstructure leading to structural relaxation effect and evolution of nanocrystalline Co(Fe) precipitates out of thermal field annealing. These materials with excellent low loss performance are obviously the most promising candidates for microwave device applications. Index Terms--Amorphous, CoFeHfO, low loss, microwave permeability.

Microstrip transmission lines with ferromagnetic Co--Ta--Zr cores are investigated in this paper. Compared to nonmagnetic devices, an increase in both inductance (x11) and quality factor (x6) is achieved in the transmission lines. The role of the magnetic material's electrical resistivity and the effect of the shape-induced anisotropy field (created by patterning the magnetic film into narrow stripes) are discussed. It is shown that the nonuniform distribution of the shape anisotropy inside the Co--Ta--Zr pattern can be used to advantage by proper placement of the signal line, thereby increasing the ferromagnetic resonance (FMR) frequency of the magnetic core. Inductance enhancement is achieved at frequencies up to ~10 GHz. Index Terms--Magnetic anisotropy, magnetic microwave devices, microstrip, planar transmission lines, soft magnetic films.

We have studied exchange coupled FePt/Fe magnetic layers using the technique of ferromagnetic resonance (FMR). The FePt layers show strong uniaxial perpendicular anisotropy, growing in the L10 epitaxial phase on MgO (100). We have considered the case for two thicknesses of Fe: 2 nm and 3.5 nm, which exhibit rigid magnet and exchange-spring behavior. All FePt thicknesses are limited to 10 nm. The FMR results display multipeaked spectra, where we have identified three Fe resonance lines in the RM sample and an extra two in the ES sample. Angular FMR studies show a strong uniaxial anisotropy induced in the Fe layer via the strong exchange coupling with the FePt film. An additional uniaxial component is also observed with an easy axis inclined by about 50[degrees] from the film normal. Supplementary magnetic measurements aid with the magnetic characterization. We also discuss the elements for the theory of FMR in these exchanged coupled systems. Index Terms--Exchange spring, magnetic bilayers, magnetic resonance, perpendicular anisotropy.

Magnetic, micromagnetic, and texture properties of the martensitic thin films prepared by magnetron sputtering of [Ni.sub.49.5][Mn.sub.28][Ga.sub.22.5] target on MgO(100) wafer are studied as a function of film thickness. The films exhibit 220-fiber texture. Moreover, in contrast to thick films, a considerable in-plane texture component is giving rise to the pronounced in-plane magnetic anisotropy found in the thin film. The texture features together with a large magnetocrystalline anisotropy lead to the particular domain structure and different magnetic anisotropy components of films depending on the film thickness and substrate nature. Index Terms--In-plane magnetic anisotropy, magnetic force microscopy, magnetization loop, Ni-Mn-Ga textured film.

The time-resolved magnetization dynamics of epitaxial [Fe.sub.3][O.sub.4] ultra-thin films grown on GaAs were investigated for the first time using a field pumped TRMOKE (time-resolved magneto-optical Kerr effect) setup. The dynamic response of the sample to the field pulse was measured for different DC bias fields applied along two orthogonal crystalline directions for 3 and 6 nm films. The results show a heavily damped precessional response to the applied field pulses. By fitting the Landau-Lifshitz-Gilbert equation to the data the temporal evolution of the magnetisation can be reproduced and the damping constant determined to be around 0.1. Index Terms--Iron oxide, magnetic anisotropy.

Epitaxial manganese substituted M-type barium ferrite thin films are deposited by alternating target laser ablation deposition (ATLAD) of Ba[Fe.sub.2][O.sub.4], [Fe.sub.2][O.sub.3], and Mn[Fe.sub.2][O.sub.4] targets. The crystal structure and the epitaxy of the films are investigated by X-ray diffraction. Surface morphology is studied by atomic force microscopy. Magnetic properties of the films are characterized by vibrating sample magnetometry and magnetization as a function of temperature measurements. Ferromagnetic resonance (FMR) measurements are utilized to study the dynamic properties of the films. Possible mechanisms for main FMR linewidth broadening as a result of Mn substitution, such as increased conductivity and the presence of Jahn-Teller effect associated with octahedrally coordinated [Mn.sup.3+] cations, are briefly discussed. Extended absorption X-ray fine structure measurements are performed to determine the cation distribution in the hexagonal unit cell. The observed 15-20% increase in saturation magnetization at 4 K and 50 K increase in the Neel temperature in comparison to bulk reference values are attributed to differences in cation distribution as a result of atomic scale deposition by the ATLAD technique. Index Terms--Cation substitution, ferromagnetic resonance, hexagonal ferrite, laser ablation deposition.