Abstract
The magnetic resonance behavior of silicon-substituted yttrium iron garnet (YIG) crystals having the average ionic composition {Y33+} [Fe1.953+Fe0.052+] (Fe2.953+Si0.054+)O12 has been investigated as a function of temperature and orientation at 9 Gc/sec. Unexpectedly, four extrema were observed in the resonance field Hres at low temperatures. For example, the values of Hres(100)=1575 Oe, Hres(111)=1985 Oe, and Hres (110)=2175 Oe were measured at 77°K. Further measurements at 24 Gc/sec indicated that g=2±0.02 from 300° to 77°K. This inverted anisotropy can be described phenomenologically by an isotropic downward shift of 1260 Oe and the cubic anisotropy fields K1/M0=200 Oe and K2/M0=−540 Oe. These K1>0 and K2<0 values are attributed to the Si4+-induced Fe2+ ions. The enormous isotropic depression of Hres is shown to be predicted by an extended formulation of the ``slow'' relaxation theory. A peak was observed in the resonance linewidth ΔH(100) of 60 Oe at about 350°K corresponding to ωτ(100)=1. Because of the appearance of multiple absorption modes due possibly to nonuniform Si substitution, the second predicted peak in ΔH could not be observed. Since the activation energy of both the resistivity and relaxation time constant τ(100) was 0.30 eV, it is suggested that the quasi-free valence electrons of the induced Fe2+ ions constitute the slow-relaxing system in YIG (Si0.05).
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
