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In this work, the reflected part of a spin-polarized electron beam is examined. A spin-polarized electron beam was obtained from a strained GaAs-type source by optically pumping the crystal with circularly polarized light. The beam was incident at a 45deg angle with respect to the surface of the ferromagnetic film. To get the maximal spin motion of the reflected electrons, it is necessary to choose...
Spin-polarized scanning tunneling microscopy and spectroscopy (SP-STM/STS) opens up new real atomic scale magnetism. Interlayer exchange coupling of ultrathin Fe(001) films grown on the antiferromagnetically stacked bct-Mn(001) layers have been studied. The ordered c(2x2)-MnAu(001) surface alloy films were studied and found a high magnetic moment for Mn spins (>4 Bohr magneton), an antiferromagnetic...
In this paper, the authors studied the ferromagnetic resonance (FMR) linewidth of thin Fe films in NM/Fe/NM structures (NM[30 Aring]=Al, Cu, Ti and Ta) to investigate the relaxation mechanism. Polycrystalline Fe films, with thicknesses of 20 to 300 Aring in steps of 20 Aring were grown by sputtering on GaAs(100) substrates. The experimental results and their interpretation agreed with the microscopic...
One of the major concerns in environmental, biomedical and other applications of enzyme is their short life time restricting its use outside the cell. An effective way to increase the stability and longevity of enzymes from hours to days is to combine them with nanoparticles. With this aim, two different catabolic enzymes-trypsin and peroxidase were attached to the uniform magnetic iron nanoparticles...
In this study we developed a novel synthesis called "ferrite route," by which we can fabricate Fe nanoparticles larger than 10 nm at a yield 10 times higher than that obtained by the above mentioned methods. Synthesis is made at 90degC, without using any hazardous materials. We found that the Fe nanoparticles via the ferrite route were more easily embedded in poly-glycidyl methacrylate (poly-GMA),...
This paper reports on magnetic properties of bulk polycrystalline samples of ln2O3 doped with a wide range of TM ions. Phase purity of the samples was analyzed by means of X-ray diffraction and conductivity was also measured using a four-probe technique. From magnetization-temperature curves (M-T curves), it was shown that Cr doped samples was found to be paramagnetic throughout the whole temperature...
Here we studied the two systems Fe/GaAs(100) and the closely related Fe/InAs(100)to determine the Fe magnetic moment as a function of thickness.Ultra-thin (0.4 -23 nm) Fe layers were epitaxially grown at RT in a UHV MBE chamber on GaAs(100) and InAs(100) substrates.The structural characterisation was performed ex-situ by high-resolution X-ray diffraction and reflectometry (XRR).Magnetic characterisation...
One to four monolayer (ML) thick Fe films grown by MBE on GaAs(100)-2times6 using scanning tunnelling microscopy was examined. Magnetic measurements have been made on the ferromagnetic 4 ML film by MOKE and BLS. It has been shown previously that in the submonolayer regime Fe prefers to nucleate islands on top of As dimer rows of the 2times6 reconstruction. We show that for thicknesses greater than...
We present here our results on the synthesis and characterization of transition metal (TM) doped-ZnO nanocrystals, where (TM= Co, Ni, Fe, Cu and Cr). Stable suspensions of these materials were produced in ethanol solution at room-temperature condition. liquors. XRD characterization of doped systems confirmed the exclusive formation of the host ZnO wurtzite structure. The incorporation of dopant species...
Detailed knowledge of magnetization reversal and possible magnetic configurations in magnetic nanostructures is essential for high-density magnetic memory. Magnetism of nanostructured magnets, of size comparable to or smaller than ferromagnetic domain size, offers a great potential for new physics. We present results of a systematic study of magnetic reversal in sub-100 nm nanodots, and how this reversal...
The formation of a parallel magnetic domain wall in the ferromagnetic (FM) Fe layer in Fe/FeF2 systems and antiferromagnetic (AF) FeF2 and MnF2 in Ni/FeF2 and Co/MnF2 bilayers as well as the magnetization reversal of uncompensated Fe interfacial moments in positively and negatively biased Ni/FeF2 was studied. Combining X-ray magnetic circular (XMCD) and linear dichroism (XMLD) measurements allows...
Particle assemblies composed of Fe particles and Fe3O4 nanoparticles are studied to obtain fundamental insight to the most appropriate approach to develop a new high permeability particle assembly.
The aim of this work is to study the mechanism of proton relaxation induced by these materials. In this sense, physicochemical and magnetorelaxometry characterization of colloidal suspensions of iron oxide and iron/iron oxide nanoparticles synthesized by laser pyrolysis were carried out and the origin of the contrast improvement was analysed. In the case of the colloidal dispersion formed by ferromagnetic...
This paper looks at the in vitro heating of low viscosity ferrofluids containing nanoparticles with elevated magnetization established by a 200 kHz AC magnetic field. It is found that controlling the concentration of the nanoparticles in solution the cPEG coated Fe nanoparticles improve the effectiveness of heating in vitro within the required limits.
The results of the effect of chromium substitution for iron on magnetocrystalline anisotropy and its temperature dependence for a series of sintered bulk Cr-substituted cobalt ferrites (CoCrxFe2-xO4 with 0lesxles0.8) over the temperature range 400 to 10 K is reported. SQUID magnetometer is used to measure major hysteresis loops at various different temperature over the range 10-400 K. It was observed...
In recent years great technological advance took place in preparation of single crystalline magnetic tunnel junctions (MTJs) with MgO(001) barriers. The theoretically predicted tunneling magnetoresistance (TMR) at room temperature of several hundred percent in Fe/MgO/Fe(001) was met by the experimental values of 180 -220%. The surface X-ray diffraction measurements on MgO/Fe(001) indicate the existence...
Both theoretical and experimental studies of the epitaxial Fe/MgO/Fe(001) trilayers have shown new spin dependent tunnelling processes due to the conservation of the (001) crystallo-graphic orientation in the entire stack. In addition the MgO barrier acts as a spin filter : the tunnelling electrons are more or less attenuated in the barrier as a function of their symmetry. The very high tunneling...
Trilayer films with two 25 nm thick SmCo5 films and intermediate Fe layer of thickness 6 nm and 16 nm have been prepared and compared with a single SmCo5 film of 50 nm thickness. Composition of the SmCo layers and individual layer thicknesses were determined by energy dispersive X-ray analysis (EDX) at various acceleration voltages. The magnetic hysteresis measured along the SmCo5 [001] orientation...
This study reports on the investigation of magnetic parameters of nanoislands Fe/MgO(001) films. Ferromagnetic resonance (FMR) analysis, atomic force microscopy (AFM), magneto-optical Kerr effect (MOKE) and magnetic force microscopy (MFM) techniques are used to characterize these nanoisland films.
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