Monodispersed magnetic nanoparticles self-organised into superlattices onto a substrate are considered to be of real interest in the development of future magnetic storage systems due to their potential ultra-high storage density, higher than 1 Tbit/cm [1]. These particles are coated by organic acids as oleic acid which act as surfactant layer and avoid coalescence and prevent possible growth o...

The probability laws associated to domain wall depinning under fields and currents have been studied in NiFe and FePt nanowires. Three basic domain wall depinning processes, associated to different potential landscapes, are found to appear identically in those systems with very different anisotropies. We show that these processes constitute the building blocks of any complex depinning mechanism...

Magnetization manipulation is essential for basic research and applications. A fundamental question is, how fast can the magnetization be reversed in nanoscale magnetic storage media. When subject to an ultrafast laser pulse, the speed of the magnetization dynamics depends on the nature of the energy transfer pathway. The order of the spin system can be effectively influenced through spin-flip ...

A family of multilayer microwires with hard/soft biphase magnetic behavior is here introduced. The microwires consist of a Fe63Pt27Si10 hard magnetic nucleus and a Fe20Ni80 soft outer shell separated by an intermediate insulating Pyrex glass microtube. The precursor FePtSi glass-coated microwire is fabricated by quenching and drawing technique, and its L10 hard magnetic phase is grown by postan...

The occurrence of chemical ordering can have a dramatic influence on structural, electronic, and magnetic properties in many materials systems. Examples of recent interest are binary metallic alloy systems such as CoPt, FePt, and FeAu, where strong interdependencies between magnetic and magneto-optical properties and the degree of long range chemical ordering have been observed. Near the equiat...

The so-called linear reversal mode is demonstrated in spin model simulations of the high anisotropy material Llo FePt. Reversal of the magnetization is found to readily occur in the linear regime despite an energy barrier (KV / kB T) that would conventionally ensure stability on this timescale. The timescale for the reversal is also established with a comparison to the Landau-Lifshitz-Bloch equ...