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Full-Text Articles in Engineering
Growth Of Crystalline Cobalt Ferrite Thin Films At Lower Temperatures Using Pulsed-Laser Deposition Technique, A. Raghunathan, David C. Jiles, Ikenna C. Nlebedim
Growth Of Crystalline Cobalt Ferrite Thin Films At Lower Temperatures Using Pulsed-Laser Deposition Technique, A. Raghunathan, David C. Jiles, Ikenna C. Nlebedim
David C. Jiles
Cobaltferritethin films were grown on SiO2/Si(100) substrates using pulsed-laser deposition technique at substrate temperatures ranging from 250 to 600 °C. Thermal expansion mismatch between the film and substrate appears to have a substantial effect on the magnetic properties of the cobaltferritefilms, due to the large magnetoelastic coupling of cobaltferrite. It was shown in this study, that polycrystalline films with (111)-preferred orientation could be prepared at substrate temperatures as low as 250 °C. The growth of crystalline cobaltferritefilms at such low temperatures indicates the potential to use cobaltferrite for microelectromechanical systemsdevices and sensor applications including integration with a wider range of …
Generalized Form Of Anhysteretic Magnetization Function For Jiles–Atherton Theory Of Hysteresis, A. Raghunathan, Y. Melikhov, J. E. Snyder, David C. Jiles
Generalized Form Of Anhysteretic Magnetization Function For Jiles–Atherton Theory Of Hysteresis, A. Raghunathan, Y. Melikhov, J. E. Snyder, David C. Jiles
David C. Jiles
A generalized form of anhysteretic magnetization function to extend Jiles–Atherton theory to different forms of anisotropy has been derived. The general equation for the function has been compared with those of calculations made on the basis of known equations for specific cases: axially anisotropic (one-dimensional), planar anisotropic (two-dimensional), and isotropic (three-dimensional). The Jiles–Atherton model using the proposed functional form of generalized anhysteretic magnetization function for anisotropy dependence has been validated and the necessary equations derived. It has been shown in this work that this functional form of anhysteretic magnetization with necessary boundary conditions can be reduced to the familiar specific …
Temperature Dependence Of Magnetic Anisotropy Of Germanium/Cobalt Cosubstituted Cobalt Ferrite, N. Ranvah, Y. Melikhov, Ikenna C. Nlebedim, David C. Jiles, J. E. Snyder, A. J. Moses, P. I. Williams
Temperature Dependence Of Magnetic Anisotropy Of Germanium/Cobalt Cosubstituted Cobalt Ferrite, N. Ranvah, Y. Melikhov, Ikenna C. Nlebedim, David C. Jiles, J. E. Snyder, A. J. Moses, P. I. Williams
David C. Jiles
The variations in magnetization and magnetic anisotropy of Ge4+/Co2+ cosubstituted cobaltferrite with temperature were investigated for a series of compositions Co1+xGexFe2−2xO4 (0≤x≤0.4). The magnetization at 5 T and low temperature were observed to increase for all Ge/Co cosubstituted samples compared to pure CoFe2O4. Hysteresis loops were measured for each sample over the magnetic field range of −5 T to +5 T for temperatures in the range of 10–400 K. The high field regions of these loops were modeled using Law of Approach to saturation, which represents the rotational and forced magnetization processes. The first order cubic magnetocrystalline anisotropy coefficient K1 …
Including Effects Of Microstructure And Anisotropy In Theoretical Models Describing Hysteresis Of Ferromagnetic Materials, H. Hauser, Y. Melikhov, David C. Jiles
Including Effects Of Microstructure And Anisotropy In Theoretical Models Describing Hysteresis Of Ferromagnetic Materials, H. Hauser, Y. Melikhov, David C. Jiles
David C. Jiles
Two recent theoreticalhysteresis models (Jiles-Atherton model and energetic model) are examined with respect to their capability to describe the dependence of the magnetization on magnetic field, microstructure, and anisotropy. It is shown that the classical Rayleigh law for the behavior of magnetization at low fields and the Stoner-Wohlfarth theory of domain magnetization rotation in noninteracting magnetic single domain particles can be considered as limiting cases of a more general theoretical treatment of hysteresis in ferromagnetism.