ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
A simple technique to analyze the effective linewidth at high field, corresponding to the far field tail of ferromagnetic resonance (FMR) absorption, was recently reported. This technique has now been applied at 10, 20, and 35 GHz to single crystal Zn2Y hexagonal ferrite with planar anisotropy. Far field effective linewidth (ΔHeffFF) measurements were made for a series of 2–3 mm-diam, 0.08–1.33-mm-thick c-plane disks. The ΔHeffFF is taken to represent the intrinsic linewidth, in the sense that there are no two magnon or inhomogeneous linebroadening contributions to the losses on the far-field FMR tail. ΔHeffFF at each frequency increases with the square of the disk thickness. This increase is consistent with an eddy current loss process. A fit of the data to a simple eddy current model yields resistivities of 10.3, 9.7, and 8.3 Ω cm at 10, 20, and 35 GHz, respectively. These values are consistent with a resistivity of 2 Ω cm from 10 GHz dielectric measurements and 20 Ω cm from the resistivity measurements.These results are similar to previous results for barium ferrite. However, the microwave response in these Zn2Y materials also shows many anomalies. First, ΔHeffFF is larger, not smaller, than the corresponding FMR linewidth. Second, ΔHeffFF also depends on the orientation of the microwave field relative to the crystallographic c plane. The losses for out-of-plane microwave pumping are larger by a factor of 2–3 than for in-plane pumping. Research sponsored by the United States Office of Naval Research, Contract N00014-90-J-4078. The single crystal samples were kindly provided by M. A. Wittenauer, Purdue University.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.354746
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