COMPOSITIONAL EVOLUTION AND MAGNETIC-PROPERTIES OF NANOCRYSTALLINE FE73.5CU1NB3SI13.5B9

Melt-spun FeCuNbSiB ribbons were annealed at 540-550-degrees-C for various times (less-than-or-equal-to 1 h). The development of a nanocrystalline structure was investigated by means of Mossbauer spectroscopy. From measured hyperfine fields and intensities the crystalline phase was inferred to be pure Fe1-xSix, with x=0.18 after 1 h annealing. The residual amorphous volume fraction was determined to be congruent-to 50%. With help of these results it has been possible to evaluate the amorphous contribution to magnetostriction in the nanocrystalline state. The development of a nanocrystalline structure was found to play a role in the main mechanisms of magnetic disaccommodation.71126008601

A STUDY OF THE AFTEREFFECT OF THE MAGNETIC-PERMEABILITY IN CO-RICH AMORPHOUS FERROMAGNETIC-ALLOYS

6093258326

Domain structure dynamics of amorphous Fe64Co21B15 and Co77B23 ribbons studied by three-dimensional neutron depolarization

Relaxation phenomena related to domain structure dynamics in amorphous ferromagnetic Fe64Co21B15, and Co77B23 samples were studied by time-resolved three-dimensional neutron depolarization and a conventional magnetic induction technique. Different initial domain structures were induced either by applying external stresses or by stress annealing. A theoretical model was developed to describe the observed time dependence of neutron depolarization upon passage through such samples. It is shown that the domain structure approaches the equilibrium state with stable domain wall positions at a rate that depends essentially both on the sample composition and on the induced magnetic anisotropy. (C) 1999 American Institute of Physics. [S0021-8979(99)01402-4].8521043104

Synthesis, magnetic and optical properties of core/shell Co1-xZnxFe2O4/SiO2 nanoparticles

The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 600°C and 800°C, respectively, for 2 h. The composition, phase, and morphology of the prepared core/shell ferrites nanoparticles were determined by X-ray diffraction and transmission electron microscopy, respectively. The diffuse reflectance and magnetic properties of the core/shell ferrites nanoparticles at room temperature were investigated using UV/VIS double-beam spectrophotometer and vibrating sample magnetometer, respectively. It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases. The cobalt ferrite nanoparticles fired at temperature 800°C; show the highest saturation magnetization while the zinc ferrite nanoparticles coated with silica shell shows the highest diffuse reflectance. On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles. These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications

FREQUENCY-DOMAIN THERMO-MAGNET MEMORY EFFECT IN THE CO75-XFEXSI15B10 ALLOYS

2553350335

MAGNETIC-PERMEABILITY AFTEREFFECT IN AMORPHOUS CO-MN ALLOYS

8841671182

MAGNETIC-PROPERTIES OF AMORPHOUS CO75-XFEXSI15B10(0-LESS-THAN-X-LESS-THAN-50)

On amorphous ribbons of the composition Co75-xFexSi15B10 (0 less-than-or-equal-to x less-than-or-equal-to 50) the Curie temperature T(C), the saturation magnetization and the magnetostriction constant lambda(S) were determined. The concentration dependence of T(C) was analysed using a molecular field model. The concentration and temperature dependence of the saturation magnetization was analysed assuming a superposition of the Fe- and Co-moments respectively. Lambda(S)(x, T) was analysed assuming the existence of a single and a two ion term.1164167115415

MAGNETIC-PERMEABILITY AFTEREFFECT AND THE TRANSITION FROM CO-RICH TO FE-RICH AMORPHOUS-ALLOYS

23512128213

MAGNETIC-BEHAVIOR OF THE RARE-EARTH BINARY R-FE ALLOYS

2553318332

THE DEVELOPMENT OF NANOCRYSTALLINE FE73.5CU1NB3SI13.5B9 - MAGNETISM AND STRUCTURAL DISORDER

In order to study the effect of the initial degree of topological disorder on the formation of the nanocrystalline state, two amorphous ribbons of composition Fe73.5CuNb3Si13.5B9 produced in different laboratories were investigated. Measurements of hysteresis loops, disaccommodation and magnetostriction were performed on as-cast and nanocrystalline samples. An analytically solvable model describing the stress dependence of the coercivity is discussed. Two types of analysis of the approach to saturation are used to estimate the distribution function of the magnetization vectors. From the pinning field, the dimension of long-range order stresses in the nanocrystalline state is deduced.134111