Title: Longitudinal χ″ of polycrystalline and impurity-doped YIG in strong rf fields
Abstract: The imaginary longitudinal susceptibility χ″ of polycrystalline YIG in a strong rf magnetic field with amplitude h behaves according to the average size x̄ of the grain size distribution p(x), to its standard deviation σ, and to the impurities' concentration c. The threshold field h̄c increases with c and with decreasing x̄. The slope of the tangent to χ″ through h̄c decreases with increasing h̄c while, if h̄c is constant, it increases with the impurity content. Taking into account Schlömann's expression for χ″ for a single crystal and a modification of Patton's transit-time-limited spin-wave lifetime model, formulas for χ″ and h̄c for an impurity-doped polycrystalline aggregate of spheres having lognormally distributed diameters are worked out. A graphical method to infer the relevant parameters from the experiment is presented. Experimental data and theory are compared on two pairs of compositions; the first one exhibiting a moderate h̄c (∼ 15 Oe) and a second one, a high h̄c ([inverted lazy s] 40 Oe). Each pair consists of a fine-grained YIG and an impurity-doped YIG. The agreement is qualitatively satisfactory. The modifications resulting from Scotter's inclusion/porosity scattering model are also briefly treated.
Publication Year: 1973
Publication Date: 1973-08-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 11
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