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Resonance Damping In Ferromagnets And Ferroelectrics, Allan Widom, Somu Sivasubramanian, Carmine Vittoria, S. Yoon, Yogendra N. Srivastava
Resonance Damping In Ferromagnets And Ferroelectrics, Allan Widom, Somu Sivasubramanian, Carmine Vittoria, S. Yoon, Yogendra N. Srivastava
Carmine Vittoria
The phenomenological equations of motion for the relaxation of ordered phases of magnetized and polarized crystal phases can be developed in close analogy with one another. For the case of magnetized systems, the driving magnetic field intensity toward relaxation was developed by Gilbert. For the case of polarized systems, the driving electric field intensity toward relaxation was developed by Khalatnikov. The transport times for relaxation into thermal equilibrium can be attributed to viscous sound wave damping via magnetostriction for the magnetic case and electrostriction for the polarization case.
Frequency-Dependence Of The Ferromagnetic-Resonance Linewidth Of Barium Ferrite, M. Elrayess, J. B. Sokoloff, C. Vittoria, W. Spurgeon
Frequency-Dependence Of The Ferromagnetic-Resonance Linewidth Of Barium Ferrite, M. Elrayess, J. B. Sokoloff, C. Vittoria, W. Spurgeon
Carmine Vittoria
Ferromagnetic resonance was measured in both a swept frequency mode of operation, in which the magnetic field was fixed, and a field swept mode, using field modulation techniques. Single-crystal spheres of 0.381, 0.305, and 0.483 mm in diameter were inserted in the waveguide and transmission was observed in the measurement. The g values for all the spheres averaged to 2.052 ± 0.011 and the uniaxial anisotropy field was 16.4 kOe. Our measurements show that the linewidth of barium ferrite is nearly independent of resonant frequency from 48 to 105 G Hz. This is in disagreement with the Kasuya-LeCraw two-magnon-one-phonon mechanism, …
Simulations Of Ferrite-Dielectric-Wire Composite Negative Index Materials, Frederic J. Rachford, Douglas N. Armstead, Vincent G. Harris, Carmine Vittoria
Simulations Of Ferrite-Dielectric-Wire Composite Negative Index Materials, Frederic J. Rachford, Douglas N. Armstead, Vincent G. Harris, Carmine Vittoria
Carmine Vittoria
We perform extensive finite difference time domain simulations of ferrite based negative index of refraction composites. A wire grid is employed to provide negative permittivity. The ferrite and wire grid interact to provide both negative and positive index of refraction transmission peaks in the vicinity of the ferrite resonance. Notwithstanding the extreme anisotropy in the index of refraction of the composite, negative refraction is seen at the composite air interface allowing the construction of a focusing concave lens with a magnetically tunable focal length.
Resonance Damping In Ferromagnets And Ferroelectrics, Allan Widom, Somu Sivasubramanian, Carmine Vittoria, S. Yoon, Yogendra N. Srivastava
Resonance Damping In Ferromagnets And Ferroelectrics, Allan Widom, Somu Sivasubramanian, Carmine Vittoria, S. Yoon, Yogendra N. Srivastava
Carmine Vittoria
The phenomenological equations of motion for the relaxation of ordered phases of magnetized and polarized crystal phases can be developed in close analogy with one another. For the case of magnetized systems, the driving magnetic field intensity toward relaxation was developed by Gilbert. For the case of polarized systems, the driving electric field intensity toward relaxation was developed by Khalatnikov. The transport times for relaxation into thermal equilibrium can be attributed to viscous sound wave damping via magnetostriction for the magnetic case and electrostriction for the polarization case.