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The buildup of stress with increasing thickness of magnetic thin films is a common phenomenon that often induces undesirable anisotropies that can convert an otherwise magnetically soft film into a magnetically hard one. We found that by interlayering such a magnetic thin film with films that are either not lattice matched or have a different crystal structure, reductions in the saturation field as large as 400-fold can be achieved. Differences in grain size appear to be responsible. [ABSTRACT FROM AUTHOR]

Reports on strong anisotropy in thin magnetic films deposited on obliquely sputtered tantalum underlayers. Fitting the angular dependence of the ferromagnetic resonance field to obtain values of anisotropy field; Microstructure of spin valve; Magnetoresistive measurements of the dispersion of the hard axis directions.

Lorentz microscopy provides a means of studying the changes in vortex lattices that are an intriguing property of type II superconductors. Lorentz microscopy is a form of electron microscopy in which two electron beams are reflected in different directions through neighboring domains.; A 300-kV Lorentz microscope yielded real-time micrographs that are far more informative than the static images produced by other micrographic techniques.

Temperature dependence of ac susceptibilities [[zeta].sup.I] and [[zeta].sup.II] are described by using frequencies for nanoparticles of Ni dispersed in silica (Ni/Si[O.sub.2]) with the mean sizes, as determined by transmission electron microscopy. The blocking temperatures [T.sub.B] are fit to the Vogel-Fulcher law and the validity of result is checked and the calculated values are consistent with experimental values.

The variations of the blocking temperature [T.sub.B] with measuring frequency [f.sub.m] and applied field H are described for Ni nanoparticles (NPs) embedded in Si[O.sub.2] matrix with the nominal composition Ni/Si[O.sub.2]. The obtained results are compared with the predictions of the Neel-Brown model of magnetic relaxation in noninteracting NPs.

Magnetic properties of nanorods of NiO, with and without oleic acid coating, are reported, and the temperature variations of the magnetization and electron magnetic resonance spectra were measured. The differences in blocking temperatures are due to stronger interparticle interaction present in the uncoated particles.

Electrical properties of damascene silver wires with widths approximately equal to 60 and 840 nm and heights approximately equal to 100 nm and 300 nm was studied. Results show that these wires exhibit significantly lower electrical resistivities if grain size could be increase significantly.

We have achieved excellent exchange decoupling of grains in CoPd multilayers by annealing in air at 300 °C. Samples exhibit a slope in the hysteresis loop close to 1.0, nucleation fields as large as 11 kOe, and coercivities as large as 16 kOe. These are among the best properties ever achieved for CoPd multilayers. In samples of the general type seed layer\ (0.3 nm Co\1 nm Pd)×15\capping layer, it appears that atoms diffuse rapidly up and down the grain boundaries at 300 °C. From x-ray photoelectron and Auger depth profiling, we have found that when Co atoms arrive at the surface they become oxidized and remain at the surface, leaving the grain boundaries depleted in Co and apparently nonmagnetic. If the annealing is carried out in vacuum, exchange decoupling of the grains does not occur. This result supports our conclusion that the presence of oxygen plays a crucial role. When Au or Pt atoms are present in the seed layer or capping layer, they diffuse into the CoPd grain boundaries and apparently enhance the exchange decoupling of grains. [ABSTRACT FROM AUTHOR]

The magnetic field determined from vanishing rotational hysteresis loss of CoCrPtB perpendicular thin film media was experimentally investigated. It was clarified that (1) in Co[sub 72]Cr[sub 16]Pt[sub 8]B[sub 4] media with d[sub mag] of less than 200 nm and Co[sub 64]Cr[sub 24]Pt[sub 8]B[sub 4] media with d[sub mag] of less than 100 nm, a homogeneous structure was realized, except for the existence of an initial growth region. (2) For both media, the perpendicular rotational hysteresis loss, W[sub r], the maximum field of W[sub r], H[sub p], and the field where W[sub r] = 0, H[sub W][sub r=0], increased with an increase in d[sub mag]. (3) For both media, H[sub W][sub r = 0] / H[sup grain][sub k] increased with an increase in d[sub mag] and saturated at a magnitude of about 1. (4) For the medium with thin magnetic film thickness, at applied field of H[sub W][sub r=o] < H < H[sup grain][sub k], a multidomain state was realized in the torque measurement in spite of no observation of loss of rotational hysteresis. This is considered to be due to the existence of thermal agitation between the multidomains. [ABSTRACT FROM AUTHOR]

It has recently been found that large uniaxial anisotropy fields in excess of 120 kA/m (1500 Oe) can be created in thin (3-5 nm) films of Co by obliquely sputtered Ta underlayers. This anisotropy can be used to pin the bottom film of a spin valve while having only a modest effect on the top "free" film, separated by a 2.5 nm Cu spacer layer. This article describes measurements of thermal stability in these Ta-pinned spin valves. Using room temperature giant magnetoresistance (GMR) as a measure, we find that the structure is stable under cumulative 20 min anneals at 25 °C intervals up to 300 °C; GMR decreases to zero upon further anneals up to 450 °C. Measurements taken at elevated temperatures reveal that GMR decreases linearly with temperature, extrapolating to zero at approximately 425 °C, while the anisotropy field is much less temperature dependent, remaining nearly constant up to 150 °C and gradually decreasing to 50% of its room temperature val! ue at 325 °C. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]