First-principle calculations are used to explore the use of magnetic degrees of freedom in catalysis. We use the Vienna Ab-Initio Simulation Package to investigate both L1 0-ordered FePt and CoPt bulk materials and perform supercell calculations for FePt nanoclusters containing 43 atoms. As the catalytic activity of transition-metal elements and alloys involves individual d levels, magnetic all...

High anisotropy, L1 0 , FePt nanoparticle assemblies consisting of 4 nm diameter particles are considered a potential data storage medium beyond 1 Tbit/in 2. However, annealing at temperatures >500°C is required to form the high anisotropy phase. Recently work on the evolution of FePt nanoparticle assemblies as a function of annealing temperature has shown that for T anneal > 650°C a substantia...

High resolution magnetic force microscopy (MFM) has been carried out on L1(0)-FePt dot arrays patterned by plasma modified nanosphere lithography. An ex situ tip magnetization reversal experiment is carried out to determine the magnetic domains and verify the imaging stability of MFM and the mutual perturbations between the magnetic tip and the sample. We have identified that the critical size ...

The effect of the Dzyaloshinsky-Moriya interaction on the magnetic structure of an ordered FePt monolayer deposited on the Pt(111) surface has been investigated. In the ground state, the pronounced anisotropic geometry of the FePt layer with alternating Fe and Pt chains gives rise to a helimagnetic structure with a strong difference in the helicity period along the chains and perpendicular to t...

An experimental approach is presented, allowing the preparation of substrate supported, hexagonally arranged metallic alloy nanoparticles with narrow size distributions, well-defined interparticle distances, and controlled chemical composition. The method is based on miniemulsion polymerization and isotropic plasma etching. Polystyrene (PS) and poly(methyl methacrylate) (PMMA) colloidsin the p...

X-ray Absorption Near Edge Structure [XANES] of FePt nanoclusters has been studied using a full multiple scattering, self-consistent field [SCF], real-space Green‘s function approach realized via the powerful ab initio FEFF8 code. One purpose of our study is to determine the sensitivity of Pt L3 edge with respect to the size and shape of the FePt nanoclusters. We also give the results of the ca...

We present designs for Ioffe-Pritchard type magnetic traps using planar patterns of hard magnetic material. Two designs are based on 40 μm foil of FePt. The first sample yields calculated axial and radial trap frequencies of 51 Hz and 6.8 kHz, respectively. For the second sample the calculated frequencies are 34 Hz and 11 kHz. The structures were produced by spark erosion and used successfully ...

Ferromagnetic nanoparticles are building blocks of future high density recording media and high performance permanent magnets. However, it is very challenging to produce nanoparticles with ferromagnetism at room temperature. The author describes recent progress in preparing ferromagnetic nanoparticles. Ferromagnetic nanoparticles can be used as building blocks for advanced bulk and thin fi lm m...