Solid State Phenomena Vols. 233-234

Abstract: Magnetic properties of nanostructures including an antiferromagnetic (NiFe)_1-хMn_x alloy have been studied for various modes of this AFM layer preparation. The possibility for application of the AFM (NiFe)_1-хMn_x alloy as a material of the pinning layer in spin valves is discussed.

Abstract: In this paper we have proposed a modified expression for the fitting M(T) data in Co-P powders with nanocorundum and nanodiamond precipitates. The expression for M(T) takes into account the effects from both thermal magnetic excitations – Bloch’s T ^3/2 law and temperature dependence of the magnetic anisotropy. The fitting parameters are spontaneous magnetization at absolute zero temperature, Bloch constant and order of magnetic anisotropy constant. The obtained Bloch constant is in good agreement with literature data. The order of magnetic anisotropy constant is found to be about 3 that is surprising result and supposedly comes from multiphase nature of the investigated Co-P powder.

Abstract: Monocrystalline silicon wafers implanted by cobalt ions with energy of 40 keV at a fluence range from 6.6×10¹² to 2.5×10¹⁷ Co⁺-ion/cm² were investigated by optical spectroscopic ellipsometry. By comparison of experimental data with modeling it is shown that the ellipsometric measurements are accurate and reliable method for monitoring of a low-dose ion implantation process.

Abstract: An ab initio study of Co monatomic nanowires (NW) magnetic properties on pure and oxygen reconstructed Cu (210) surface was performed. Strong influence of oxygen surface impurity on MAE in Co nanowire was found. High value of magnetic moment and small energy of magnetic anisotropy (MAE) were obtained in Co nanowires on pure Cu (210) surface. After oxygen reconstruction of Cu (210) surface (Cu (210)-(2×1)O) the significant enhancement of MAE was found in Co nanowires, while the magnetic moment of Co atoms is practically unchanged. Oxygen on Cu (210) surface rotates easy magnetization axis in Co NW with respect to the pure surface.

Abstract: Three new coordination compounds of iron (II), [Fe (HC(Pz)₃)₂](C₈H₅O₄)₂^.C₈H₆O₄ (I), [Fe (HC(Pz)₃)₂](C₁₀H₇SO₃)₂^.2H₂O (II) and Fe (HC(Pz)₃)₂](C₁₂H₂₅SO₄)₂ (III), where HC(Pz)₃ is the tridentate chelator tris(pyrazol-1-yl) methane, have been synthesized and investigated by X-ray structure analysis, electronic and IR spectroscopy, static magnetic susceptibility method. The magnetochemical study of complexes I–III in the interval from 300 to 500 K showed that they possessed the high-temperature spin crossover ¹A₁ ↔ ⁵T₂ accompanied by thermochromism (the pink ↔ white color change).

Abstract: The films of heterogeneous systems based on ferromagnetic alloy and С were obtained by ion-beam sputtering. The concentration dependence of the resistance of composites was measured before and after heat treatment. The research of magnetostatic and magnetodynamic properties of heterogeneous metal-carbon showed that compounds (Co)_Х(C)_100-Х (Co₄₀Fe₄₀B₂₀)_Х(С)_100-Х (Co₄₅Fe₄₅Zr₁₀)_Х(C)_100-Х after the percolation threshold have good soft magnetic properties.

Abstract: Nanoclusters and nanocrystals of the room temperature magnetic spinel CuCr₂S₄ synthesized using a facile solution-based method were examined by magnetic resonance in a wide frequency range 9.6÷80 GHz and at temperatures down to 4.2 K. Decreasing of the resonance field and broadening of the resonance lines are found below ∼ 50 K for both the nanocluster and nanocube samples due to the freezing of magnetic moments of nanocubes and nanocrystalline particles constituting nanoclusters. Additional blocking temperature T_b≅300 K appears in nanoclusters due to the freezing of the magnetic moment of the entire cluster as a whole. Below this temperature, an additional low-field resonance line is found in the resonance spectra of nanoclusters at X-band.

Abstract: We present ab initio study of the magnetic properties of monatomic 3d transition metal (Mn, Fe, Co, Ni) nanowires without and with oxygen atoms on vicinal Rh (553) surface. We considered different experimentally observed submonolayer quantities of oxygen atoms. It was found that monatomic 3d metal nanowires without oxygen are in magnetic states. Within oxidized metal nanowires oxygen atoms affect on the magnetic moments and magnetic interaction of metal atoms. This influence leads to reduced (in the case of Mn, Fe and Co atoms) or quenched (in the case of Ni atoms) magnetic moment for these metal atoms.

Abstract: In this article, we study the intrinsic magnetic properties of diluted FeCo clusters nanoparticles embedded in an inert amorphous carbon matrix. We report an enhancement of the magnetic anisotropy energy (MAE) after annealing demonstrated by superconducting quantum interference device (SQUID) measurements and adjustments. Rutherford backscattering spectrometry (RBS) was used to quantify the sample stoichiometry and concentration.

Abstract: Hysteresis loops were plotted and dependence of coercive field, residual saturation magnetization and saturation magnetization on size of the Co-Au core-shell nanoparticles were calculated within the developed model. It was shown that decrease in the size of nanoparticles leads to decrease of the abovementioned characteristics. Calculated values of the hysteresis characteristics ​​are in good agreement with the experimental data.