The underlying mechanism of coercivity in permanent magnets has been a topic of intense interest for many years. It is motivated by the fact that the measured coercivity approaches only 20%–40% of the theoretical nucleation fields as derived from micromagnetic theory. We address this problem by proposing an analytical model, within the framework of the micromagnetic approximation, to examine th...

Lorentz microscopy combined with conventional transmission electron microscopy were used to image the magnetic domains and microstructures of sintered Sm~CobalCuxFe0.06Zr0.03)z ~0.088<x <0.128; 5.8<z<7.2! permanent magnets which were specifically designed for high temperature applications. The microstructural data were correlated with the magnetic measurements to understand the origin of coerci...

We study connections between four different types of results that are concerned with vector-valued functions u : Ω → R of class L(Ω) on a domain Ω ⊂ R: Coercivity results in H(Ω) relying on div and curl, the Helmholtz decomposition, the construction of vector potentials, and the global div-curl lemma. Key-words: Friedrichs inquality, coercivity, div-curl lemma, compensated compactness

Abstract. Some criteria for the asymptotic stability of nonlinear stochastic partial differential equations with variable delays are presented. A coercivity condition plays the role of an exponential stability criterion. Consequently, under the coercivity condition almost all the trajectories of the nonstationary solutions of the given stochastic system finally tend exponentially to zero. Two e...

The structures and magnetic properties of Pr–Fe–Al alloys produced by the metallic mold casting method were investigated. The Pr–Fe–Al alloy consisted of the amorphous phase together with the non-ferromagnetic Pr phase. Magnetic measurements confirmed that the origin of coercivity in the alloys was the amorphous phase. It was found that the Curie temperature and coercivity of the alloys were st...

Fe(x)Pt(y)Au(100-x-y) nanoparticles of size 3.5 nm were prepared by polyol reduction of platinum acetylacetonate and gold acetate and the thermal decomposition of iron pentacarbonyl. The as-synthesized nanoparticles with disordered fcc structure were then heat treated to transform to the L1(0) structure with high magnetocrystalline anisotropy. By tuning the stoichiometry of the Fe(x)Pt(y)Au(100...

Thin 001 textured FePt and CoPt polycrystalline films (5 nm) were deposited with an MgO polycrystalline underlayer on an oxidized Si substrate followed by a Rapid Thermal Annealing (RTA) process. Structural analysis indicated the samples to be fully ordered after 10 minutes (min) of RTA at 700 C. The magnetic hysteresis exhibited strong perpendicular anisotropy and a coercivity ( ) between 6 an...

In this study, we demonstrated the magnetoelectric control of magnetic thin films. (111)-textured Pd/Ni/ Pd thin films were prepared on mica/lead zirconium titanate (PZT) substrates for the investigation. The reversible modulation of magnetic coercivity in Ni films was observed through the electric-voltagecontrolled strain variation from the PZT substrate. For 14 nm Ni film, the applied electri...