Universitat de Barcelona
Mostrando ítems 1-20 de 1246
We study the effect of a magnetic field on the martensitic transition of a Cu-Al-Mn shape-memory alloy. The martensitic transition has been studied through resistance measurements under applied magnetic fields ranging from ...
Co-Ti-Sn-Ge substituted M-type bariumhexaferrite powders with mean grain sizes between about 10 nm and about 1 ¿m and a narrow size distribution were prepared reproducibly by means of a modified glass crystallization method. ...
CoFe-Ag-Cu granular films, prepared by rf sputtering, displayed magnetic domain microstructures for ferromagnetic concentrations above about 32% at, and below the percolation threshold. All samples have a fcc structure ...
We have studied the structural and magnetic properties of colloids consisting of different concentrations of magnetite particles dispersed in kerosene. Our data for the temperature dependence of the low field magnetization ...
The magnetization process of Co/Al oxide/Py trilayers and its evolution with the temperature have been analyzed. The particular behavior of the Co layers, including the shift of the hysteresis loops and a coercivity increase ...
In this paper evidence of a spin glass behaviour in FeSbO 4 rutile from susceptibility and hysteresis loop measurements are presented. The spin glass transition has as a precursor effect a strong deviation of the Curie-Weiss ...
The particle orientation in several Y-Fe2O3magnetic tapes has been quantitatively evaluated by using the data of both Mössbauer and hysteresis loop measurements performed in the three orthogonal directions. A texture ...
Several NdFeB compositionally modulated thin films are studied by using both conversion electron Mossbauer spectra and SQUID (superconducting quantum-interference-device) magnetometry. Both the hyperfine fields and the ...
Conversion electron Mossbauer spectra of composition modulated FeSi thin films have been analysed within the framework of a quasi shape independent model in which the distribution function for the hyperfine fields is assumed ...
Magnetization versus temperature in the temperature interval 2-200 K was measured for amorphous alloys of three different compositions: Fe 81.5B14.5Si4, Fe40Ni38 Mo4B18, and Co70Fe5Ni 2Mo3B5Si15. The measurements were ...
Spin-dependent tunnel junctions with the structure (Ta 70 /spl Aring//NiFe 70 /spl Aring//MnIr 80 /spl Aring//CoFe 35 /spl Aring//HfAlO/sub x//CoFe 35 /spl Aring//NiFe 40 /spl Aring//TiW(N) 150 /spl Aring/) were fabricated ...
In this paper, a remote O2 ion source is used for the formation of nano-oxide layers. The oxidation efficiency was measured in CoFe-oxide films, and a decrease of the oxide layer with the pan angle and the oxidation pressure ...
Real-world images are complex objects, difficult to describe but at the same time possessing a high degree of redundancy. A very recent study [1] on the statistical properties of natural images reveals that natural images ...
The synthesis of magnetic nanoparticles with monodispere size distributions, their self assembly into ordered arrays and their magnetic behavior as a function of structural order (ferrofluids and 2D assemblies) are presented. ...
The synthesis of spinel ferrites with composition Zn1-2xNaxFe2+xO4has been performed and the composition range in which single phase samples are obtained has been defined. The characterization of the samples has been carried ...
With the aim of a better understanding of both cationic distribution and magnetic properties of the uniaxial SrFe12-xCrxO19hexagonal ferrites, Mössbauer spectroscopy, neutron diffraction and high field magnetization ...
We have studied the static magnetic properties of nanocrystalline Co-Ti doped barium ferrite BaFe/sub 10.4/Co/sub 0.8/Ti/sub 0.8/O/sub 19/. The zero-field-cooled (ZFC) and field-cooled (FC) processes show the typical ...
Several ribbons of composition Fe73.5Cu1Nb 3Si16.5B6 and Fe73.5Cu1 Nb3Si13.5B9 were prepared by annealing the as-quenched samples between 525°C and 700°C; which induced nucleation of nanocrystallites of Fe bcc-type ...
A generalized off-shell unitarity relation for the two-body scattering T matrix in a many-body medium at finite temperature is derived, through a consistent real-time perturbation expansion by means of Feynman diagrams. ...
A systematic time-dependent perturbation scheme for classical canonical systems is developed based on a Wick's theorem for thermal averages of time-ordered products. The occurrence of the derivatives with respect to the ...
