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Sputtered thin films of amorphous Fe67Co18B15, which have high resistivity and high saturation magnetization, were studied.

The fundamental physical properties of epitaxial FeTaN alloy and the part they play in determining the soft magnetic properties of nanocrystalline films, have been explored. Hoffmann's ripple theory, using the Doyle-Finnegan calculation of local average anisotropy, was the theoretical model for the approach. Deposition conditions were optimized on Cu(001)/Si(001) single crystal substrates and Fe growth was in agreement with earlier reports. Magnetocrystalline anisotropy and magnetostriction constants were influenced by tantalum and nitrogen additions.

The magnetic and structural characteristics of phase separated Co-rich CoAg very thin films are examined as a function of film thickness and Co concentration. Grain growth is promoted and a severe change in the magnetic properties is observed after annealing at 420 degrees C for half an hour in high vacuum. The large coercivity values obtained in very thin films and the relatively large magnetization and high squareness are encouraging for potential applications as magnetic recording media.

In-plane x-ray diffraction method was used for examining the lattice strain in sputtered epitaxial Co80Pt20 films. The lattice strain magnitude observed in the epitaxial films is smaller than the calculated mismatch between the Co80Pt20 and the underlayer even at a thickness of 1 nm.

The investigation of the effects of the Ru(sub x)Cr(sub 1-x)/Ta underlayer on the microstructural and magnetic properties of CoCrPtB perpendicular films is discussed. The increase in Cr concentration from 0 percent to 40 percent led to an improvement in the c-axis anglar dispersion of (0002) CoCrPtB magnetic layers.

Research into Co/Pd multilayers deposited on either Ta or indium tin oxide seed layers as a possible perpendicular recording media is presented. It is concluded that the indium tin oxide underlayer is beneficial to the basic perpendicular magnetic media properties. It gives a magnetic multilayer that is less exchanged coupled than the Ta underlayer.

Soft-magnetic properties of Fe-Co-B thin films with an amorphous structure are studied. The soft-magnetic properties of these films show a strong dependence on the film deposition bias voltage, which presumably changes the microstructure of the films and the related magnetic anisotropy.

There is great interest both in the magnetic recording and wireless phone industries in the development of magnetic films with permeabilities that reach out into the GHz frequencies. Thus, in this study, the permeability of a thin film of Mo permalloy is measured up to 3 GHz utilizing a strip loop device.

A study of the microstructural and magnetic properties of phase separated Co-rich CoAg very thin films is presented. In the as-deposited state these films form in a very fine grained metastable alloy and are magnetically soft ([H.sub.c]e [less than] 20 Oe) in the thickness (5 - 50 nm) and Co composition range investigated (Co volume percent [greater than] 65 %). After annealing at 420 [degrees] C for 30 minutes phase separation and grain growth occur and the coercivity is now thickness dependent with a maximum around 15 nm. The maximum coercivity as a function of composition is expected to occur around a volume concentration of 50 % for bulk or thick film granular materials. However, for films thinner than 20 nm we have found a maximum He [greater than] 800 Oe at a Co concentration of 70 vol %. This shift in the percolation threshold may originate in the reduced dimensionality of very thin films. Magnetic force microscopy images show a transition in the magnetic domain structure as a function of film thickness that is consistent with this description and the results obtained by transmission electron microscopy. Index Terms - Co-Ag thin films, granular materials, high coercivity, percolation threshold.

The magnetostriction constants, [[Lambda].sub.100] and [[Lambda]y[.sub.111], of FeTaN (10 wt% Ta) were determined in (110) oriented epitaxial thin films ([equivalent] 1500 [Angstrom],) deposited by dc magnetron sputtering onto Cu(001) buffer layers ([approximately]2000 [Angstrom]) which were grown on Si(001) single crystal substrates. The orientation relationship of the films was FeTaN(110)[parallel to]Cu(001)[parallel to]Si (001) with FeTaN[parallel to]Cu [parallel to] Si, which was satisfied by four different, equally probable in-plane orientations of the crystallites. The magnetostriction measurement was carried out on a cantilever beam measurement system calibrated with (110) oriented epitaxial Fe films with the same morphology as the unknown films assuming the bulk values of [[Lambda].sub.100] and [[Lambda].sub.111]. The magnetostriction of FeTaN films was measured as a function of angle in the sample plane and fitted with the calculated average of the four orientations. In conflict with theoretical predictions, it was found that [[Lambda].sub.100] decreases and [[Lambda].sub.111] increases as a function of lattice dilation which was taken to be proportional to the interstitial concentration. At larger normalized lattice dilation, [approximately]2%, [[Lambda].sub.111] changed sign from negative to positive. The calculated saturation magnetostriction, [[Lambda].sub.s], using these values of [[Lambda].sub.100] and [[Lambda].sub.111], agreed with published data on nanocrystalline samples of the same composition with no additional assumptions. Index Terms - FeTaN, magnetostriction, nanocrystalline alloys.

The temperature dependence of the coercivity of ultrathin NiFe films was measured by SQUID in the temperature range from 5 to 300 K. The change in coercivity with temperature was much greater for thinner films than for thicker ones. A domain wall motion model is proposed to explain the experimental results. It is concluded that the intrinsic coercivity increases rapidly with decreasing the thickness, especially in the range of several nm, and that the low coercivity observed for very thin films at room temperature is ascribed primarily to the thermal effect.

The microstructure of [Co.sub.90][Fe.sub.10]/Ag GMR multilayer films has been investigated using x-ray diffraction (XRD) and cross-sectional transmission electron microscopy (XTEM). Columnar grain growth with a (111) fiber texture is observed. A direct correlation is made between superlattice satellite peak signals from selected area electron diffraction (SAD) and XRD.

Initial permeability and transverse bias permeability measurements have been made on [NiFeCo(t)/Cu(23[Angstrom])]6 multilayers for different magnetic layer thicknesses(t) in the as-deposited state and after an annealing treatment. The initial permeability was found to be independent of frequency up to at least 100 MHz and to increase with magnetic layer thickness. The transverse bias permeability is used to calculate the effective uniaxial anisotropy and the bilinear and biquadratic exchange fields. The thicker multilayers are found to be ferromagnetically coupled in the as-deposited state and upon annealing a transition occurs producing antiferromagnetically coupled magnetic layers.

The structural and magnetic properties of 10 nm FePt thin films annealed by using a 1064 nm wavelength laser are examined. In-plane x-ray diffraction analysis has shown that the laser annealed grain size is smaller than that of furnace annealed sample for an equivalent order parameter demonstrating the merit of short time annealing.

Dynamic remanent hysteresis loops are used to determine both the SFD (determined by the anisotropy energy distribution and the interaction) and the thermal energy barrier distribution (determined by anisotropy energy distribution, grain size distribution, and the interaction) of a chemically ordered L1(sub 0) Fe45Pt55 nanoparticle. In comparison with the particle area distribution width obtained from the TEM image, the energy barrier distribution width is greatly reduced due to strong interparticle exchange interaction.

A computational model used to study the magnetic properties of high anisotropy granular materials, with emphasis on a comparison with experimental data is presented. It also shows that the use of Sharrock law gives erroneous results in systems with significant superparamagnetic components.

Ga implantation during focused-ion-beam (FIB) milling of metallic magnetic materials for magnetic recording heads was examined using Auger electron spectroscopy (AES). The Ga concentration profiles were characterized in two directions: in the depth direction (parallel to the incident beam) and in the lateral direction (perpendicular to the incident beam). The sample for AES analyses in the depth direction was prepared by FIB etching of a plated Ni78.5Fe21.5 film surface. The AES depth profile showed a maximum implanted Ga concentration of ∼20 at. % at a distance of ∼15 nm, and the tail of the implantation profile reached more than 100 nm. The sample for the lateral direction analyses was prepared by cutting a cross-sectional specimen out of the air-bearing surface of a working recording head. The lateral profile showed a maximum implanted Ga concentration of 47 at. % at the surface, with a lateral implantation depth of ∼10 nm. These results were compared with results predicted by a Monte Carlo implantation simulation package (TRIM). The simulated lateral profile was reasonably consistent with experimental observation, but the simulated depth profile agreed with experiment less well. Specifically, it did not predict the observed concentration levels observed as deep as 100 nm, which are believed to be due to dynamical sputtering effects. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Investigates magnetostriction properties of a deformed and annealed copper (Cu)-iron (Fe) alloy. Magnetostriction value in cold-rolled and recrystallized sample; Saturation magnetostriction; Heat-treatment processing.

Examines the exchange induced unidirectional anisotropy in chromium-aluminum antiferromagnetic films. Measurement of the temperature dependence of the exchange field; Location of dominant domain wall pinning forces in the ferromagnetic layer; Estimation of the exchange coupling energy and magnetic anisotropic constant.