Search results for " Magnetic ordering"

showing 3 items of 3 documents

Strain-controlled domain wall injection into nanowires for sensor applications

2021

We investigate experimentally the effects of externally applied strain on the injection of 180$^\circ$ domain walls (DW) from a nucleation pad into magnetic nanowires, as typically used for DW-based sensors. In our study the strain, generated by substrate bending, induces in the material a uniaxial anisotropy due to magnetoelastic coupling. To compare the strain effects, $Co_{40}Fe_{40}B_{20}$, $Ni$ and $Ni_{82}Fe_{18}$ samples with in-plane magnetization and different magnetoelastic coupling are deposited. In these samples, we measure the magnetic field required for the injection of a DW, by imaging differential contrast in a magneto-optical Kerr microscope. We find that strain increases t…

Materials scienceCondensed matter physics530 PhysicsNanowireNucleationGeneral Physics and AstronomyFOS: Physical sciences02 engineering and technologyPhysics - Applied PhysicsApplied Physics (physics.app-ph)Coercivity021001 nanoscience & nanotechnology530 Physik01 natural sciencesMagnetic fieldMagnetizationMagnetic anisotropyCondensed Matter::Materials ScienceDomain wall (magnetism)Materials properties Magnetic hysteresis Ferromagnetic materials Magnetic anisotropy Magnetic devices Sensors Nanowires Magnetic ordering Magnetic materials0103 physical sciences010306 general physics0210 nano-technologyAnisotropy
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Size effect in phase transition kinetics

1988

The growth of a spontaneous lattice average magnetization in a magnetic system which is suddenly brought below the transition temperature is a stochastic process in which the very small fluctuations of the initial magnetization are amplified to a macroscopic size. The initial magnetization fluctuates in time around the zero average value because of the finite size of the system. As a consequence of the fluctuation-amplification phenomenon the nonlinear relaxation of the finite system is qualitatively different from that of the infinite one. The present paper studies this feature of phase-transition kinetics in the framework of a very simple model: the dynamical generalization of the spheric…

PhysicsPhase transition kineticsCondensed matter physicsStochastic processtheory and models of magnetic ordering; magnetic phase transitions; relaxation phenomena in magnetic systemsTransition temperatureKineticsmagnetic phase transitionsSpherical modelNonlinear systemMagnetizationLattice (order)Statistical physicstheory and models of magnetic orderingrelaxation phenomena in magnetic systems
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Kinetics of Ordered Phases in Finite Spin Systems

1989

We study the growth of the ordered phase in a spin system of finite size suddenly brought below the transition temperature. Such a growth is driven by the instability of the mode corresponding to the largest eigenvalue of the interaction matrix. The relaxation occurs through different regimes according to whether the unstable mode has a negligible or macroscopic amplitude. One regime is characterised by dynamical scaling properties whereas in the other we can distinguish the growth to a macroscopic amplitude followed by rare transitions from one equilibrium amplitude to another. The analysis is carried out in the framework of a dynamical generalisation of the spherical model assuming non-ra…

PhysicsSpin glassCondensed matter physicsSpin polarizationSpinsRelaxation (NMR)magnetic phase transitionsCondensed Matter PhysicsInstabilitygeneral models of magnetic orderingAtomic and Molecular Physics and Opticsnumerical models of phase transitionsSpherical modelAmplitudeMathematical Physicsmagnetic phase transitions; general models of magnetic ordering; numerical models of phase transitionsSpin-½Physica Scripta
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