Josef Fidler

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A parallel finite element micromagnetics package has been implemented, which is highly scalable, easily portable and combines different solvers for the micromagnetic equations. The implementation is based on the standard Galerkin discretization on tetrahedral meshes with linear basis functions. A static energy minimization, a dynamic time integration and(More)
The ffite element method effectively treats the irregular microstructure of nanocrystalline magnets. Thus precise theoretical predictions of the magnetic properties are possible, taking into account microstructural features such as grain size, particle shape and intergranular phases. The hysteresis properties either follow form the direct minimization of(More)
CoPt nanoparticles with an average size of 3 nm and narrow distribution were synthesized by chemical reduction of Co(CH(3)COO)(2) and Pt(acac)(2) by polyethyleneglycol-200. The as-prepared nanoparticles have a disordered fcc structure which transformed after thermal treatment to an ordered fct structure, which results in coercivity up to 6 kOe at room(More)
We studied exchange coupled composite (ECC) media with an out-of-plane easy axis consisting of hard magnetic L1(0) chemically ordered FePtCu alloy films and magnetically softer [Co/Pt](N) multilayer stacks. By tailoring the structural properties of the ternary FePtCu alloy and [Co/Pt](N) multilayers, we can tune the magnetic parameters of the composite in a(More)
Chemically ordered 5 nm-thick L1₀ FePtCu films with strong perpendicular magnetic anisotropy were post-patterned by nanoimprint lithography into a dot array over a 3 mm-wide circumferential band on a 3 inch Si wafer. The dots with a diameter of 30 nm and a center-to-center pitch of 60 nm appear as single domain and reveal an enhanced switching field as(More)
Patterned media shows great potential for future ultrahigh-density magnetic recording. The thermal stability is determined by the relevant transition states. We apply the nudged elastic band method to calculate energy barriers and thermal reversal modes as a function of the island size and intergrain exchange coupling. Nonuniform reversal modes and(More)
Exchange spring media are proposed for magnetic-recording systems consisting of a hard/soft bilayer. By varying the fraction of thickness for the hard and soft layer and by varying their saturation polarizations, the media properties can be optimized in order to achieve high thermal stability without increase of coercive field. In grains with identical size(More)
We performed micromagnetic simulations in order to investigate the effect of intergranular exchange coupling on the magnetic properties of advanced magnetic recording structures. We found that the coercive field of granular recording media decreases with increasing intergrain exchange coupling (<i>A</i> <sub>int</sub>). We observed this decay even for(More)