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Magnetization in quasiperiodic magnetic multilayers with biquadratic exchange coupling
A theoretical study of the magnetization curves of quasiperiodic magnetic
multilayers is presented. We consider structures composed by ferromagnetic
films (Fe) with interfilm exchange coupling provided by intervening
nonferromagnetic layers (Cr). The theory is based on a realistic
phenomenological model, which includes the following contributions to the free
magnetic energy: Zeeman, cubic anisotropy, bilinear and biquadratic exchange
energies. The experimental parameters used here are based on experimental data
recently reported, which contain sufficiently strong biquadratic exchange
coupling.Comment: 6 EPS figures, REVTeX, accepted for publication in Journal of Applied
Physic
Near-Field Microwave Microscopy of Materials Properties
Near-field microwave microscopy has created the opportunity for a new class
of electrodynamics experiments of materials. Freed from the constraints of
traditional microwave optics, experiments can be carried out at high spatial
resolution over a broad frequency range. In addition, the measurements can be
done quantitatively so that images of microwave materials properties can be
created. We review the five major types of near-field microwave microscopes and
discuss our own form of microscopy in detail. Quantitative images of microwave
sheet resistance, dielectric constant, and dielectric tunability are presented
and discussed. Future prospects for near-field measurements of microwave
electrodynamic properties are also presented.Comment: 31 pages, 9 figures, lecture given at the 1999 NATO ASI on Microwave
Superconductivity Changes suggested by editor, including full reference
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