The Experts below are selected from a list of 1503 Experts worldwide ranked by ideXlab platform
S A Nikitov - One of the best experts on this subject based on the ideXlab platform.
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bragg resonances of magnetostatic surface spin waves in a layered structure magnonic crystal dielectric metal
Applied Physics Letters, 2012Co-Authors: E N Beginin, Yu A Filimonov, E S Pavlov, S L Vysotskii, S A NikitovAbstract:It is experimentally shown that metal cladding of the surface of a one-dimensional magnonic crystal destroys the Bragg band gaps in microwave transmission spectra of propagating magnetostatic surface spin waves in magnonic crystal. This is a consequence of violating a phase synchronism condition of forward and reflected by a magnonic crystal magnetostatic surface wave. When a magnetostatic surface wave propagates in a layered structure, ferromagnetic film with a magnonic crystal-dielectric layer-metal cladding this synchronism condition can also be fulfilled, not depending on the thickness of a dielectric layer.
Manfred Ernst Schabes - One of the best experts on this subject based on the ideXlab platform.
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micromagnetic analysis of the effect of intergranular exchange on thermal stability in magnetic recording iii perpendicular media
IEEE Transactions on Magnetics, 2002Co-Authors: Hong Zhou, H N Bertram, Manfred Ernst SchabesAbstract:We describe micromagnetic simulations to examine the effect of intergranular exchange on thermal stability of dibit transitions in perpendicular media. We found that, without an intergranular exchange, pure magnetostatic interactions induce substantial magnetization decay; a weak exchange, however, reduces the decay significantly. In addition, the reduction is more pronounced at reduced magnetostatic interactions. To achieve a high signal-to-noise ratio (SNR) and reduce thermal decay simultaneously, a medium with reduced magnetostatic interactions is required and a weak exchange should be included. Reducing the spacing between the soft underlayer and the recording medium enhances thermal stability. The effect is more pronounced at higher linear densities.
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effect of intergranular interactions on thermal energy barrier distribution in perpendicular media
Journal of Applied Physics, 2002Co-Authors: Hong Zhou, Neal H Bertram, Manfred Ernst SchabesAbstract:Micromagnetic simulations have been performed to simulate dynamic hysteresis loops in perpendicular media. Thermal energy barrier distributions have been calculated. For a fixed percentage of magnetization switched, a linear variation between the scaled applied field Ha(t)/HK and ln(f0t)1/2 is found. Without including intergranular magnetostatic interactions, intergranular exchange coupling reduces the thermal energy barrier distribution width, compared to the physical volume distribution width. However, the magnetostatic interactions increase the energy barrier width substantially. The increase is significantly reduced at smaller magnetostatic interactions. For the effective volume of 50% magnetization switched (V50), the results show V50=〈V2〉 almost independent of intergranular magnetostatic and exchange interactions.
Valentyn Novosad - One of the best experts on this subject based on the ideXlab platform.
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effect of interdot magnetostatic interaction on magnetization reversal in circular dot arrays
Physical Review B, 2002Co-Authors: Valentyn Novosad, Yu K Guslienko, H Shima, Yoshichika Otani, S G Kim, K Fukamichi, Nobuaki Kikuchi, O Kitakami, Y ShimadaAbstract:The effect of the interdot magnetostatic interaction on the magnetization reversal due to the ``nucleation'' and ``annihilation'' of magnetic vortices in arrays of ferromagnetic submicron circular dots has been investigated experimentally and theoretically. The magnetostatic interaction plays an important role in magnetization reversal for the arrays with a small interdot distance, leading to decreases in the vortex nucleation and annihilation fields, and an increase in initial susceptibility.
Jordi Pratcamps - One of the best experts on this subject based on the ideXlab platform.
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circumventing magnetostatic reciprocity a diode for magnetic fields
Physical Review Letters, 2018Co-Authors: Jordi Pratcamps, Patrick Maurer, Gerhard Kirchmair, O RomeroisartAbstract:Lorentz reciprocity establishes a stringent relation between electromagnetic fields and their sources. For static magnetic fields, a relation between magnetic sources and fields can be drawn in analogy to the Green’s reciprocity principle for electrostatics. So far, the magnetostatic reciprocity principle remains unchallenged and the magnetostatic interaction is assumed to be symmetric (reciprocal). Here, we theoretically and experimentally show that a linear and isotropic electrically conductive material moving with constant velocity is able to circumvent the magnetostatic reciprocity principle and realize a diode for magnetic fields. This result is demonstrated by measuring an extremely asymmetric magnetic coupling between two coils that are located near a moving conductor. The possibility to generate controlled unidirectional magnetic couplings implies that the mutual inductances between magnetic elements or circuits can be made extremelly asymmetric. We anticipate that this result will provide novel possibilities for applications and technologies based on magnetically coupled elements and might open fundamentally new avenues in artificial magnetic spin systems.
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negative permeability in Magnetostatics and its experimental demonstration
Physical Review B, 2017Co-Authors: Rosa Machbatlle, Albert Parra, Jordi Pratcamps, Sergi Laut, Carles Navau, A SanchezAbstract:The control of magnetic fields, essential for our science and technology, is currently achieved by magnetic materials with positive permeability, including ferromagnetic, paramagnetic, and diamagnetic types. Here we introduce materials with negative static permeability as a new paradigm for manipulating magnetic fields. As a first step, we extend the solutions of Maxwell magnetostatic equations to include negative-permeability values. The understanding of these new solutions allow us to devise a negative-permeability material as a suitably tailored set of currents arranged in space, overcoming the fact that passive materials with negative permeability do no exist in Magnetostatics. We confirm the theory by experimentally creating a spherical shell that emulates a negative-permeability material in a uniform magnetic field. Our results open new possibilities for creating and manipulating magnetic fields, which can be useful for practical applications.
Y Shimada - One of the best experts on this subject based on the ideXlab platform.
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effect of interdot magnetostatic interaction on magnetization reversal in circular dot arrays
Physical Review B, 2002Co-Authors: Valentyn Novosad, Yu K Guslienko, H Shima, Yoshichika Otani, S G Kim, K Fukamichi, Nobuaki Kikuchi, O Kitakami, Y ShimadaAbstract:The effect of the interdot magnetostatic interaction on the magnetization reversal due to the ``nucleation'' and ``annihilation'' of magnetic vortices in arrays of ferromagnetic submicron circular dots has been investigated experimentally and theoretically. The magnetostatic interaction plays an important role in magnetization reversal for the arrays with a small interdot distance, leading to decreases in the vortex nucleation and annihilation fields, and an increase in initial susceptibility.