Papers by Keyword: Magnetisation

Abstract: In the present work, we have reported the effect of cobalt concentration on Bi_0.95Ba_0.05Fe_1-xCo_xO₃ (where x = 0.01, 0.03, 0.05) synthesis by solvothermal method. The structural properties are studied using X-ray diffraction by performing Rietveld analysis. The change in magnetic properties is associated with bond angle. The leakage current density mechanism is studied by measuring I-V characteristics.

Abstract: Co₂FeO₄ spinel oxide nano powder was synthesized by co-precipitation process. Samples were annealed at different temperatures of 500, 800 and 900^o C and the phase purity were also analyzed. As-prepared sample has two spinel phases and on annealing at 900 ^οC single phase compound formed. The crystallite size of as-prepared is found to be 11.9 nm. The crystallite size increased with increase in annealing temperature to a maximum of 17.4 nm for 900 °C. Samples were subjected to necessary characterization for finding thermal, magnetic and optical band gap.

Abstract: Two series of Zn doped Rh perovskites LaRh1-2xCux ZnxO3 and La0.75Pb0.25Rh1-2xCuxZnxO3 (0≤ x ≤0.25) were synthesised by solid-state methods and their crystallographic, magnetic, and electric properties investigated. Both series have an orthorhombic perovskite-type structure in space group Pbnm. The increase in Zn content has an obvious impact on the electron delocalisation in which the shift in the average valency of Cu and Rh (+2.5 and +3.5) has resulted in a reduction in cell volumes and an increase in the effective magnetic moments. The Curie–Weiss magnetization curves measured between 5-300K are indicative of antiferromagnetism. The addition of Pb to the A- site decreases the conductivity as anticipated.

Abstract: This research investigates the mechanical property of the concrete which were mixed with chemical admixtures and treated by magnetic field. Two chemical admixtures were used in this research: Concrete superplasiticizer SW-4 and early strength admixtures CF. Magnetic treated admixtures were obtained by passing liquors through a concrete magnetic-field-generating machine. Test variables included admixture dosage and curing age. Results show that liquor’s conductivity and surface tension have some special changes after treated by magnetic field, and using magnetic treated admixtures could improve the compressive strength of the concrete, reduce the setting times and improve its fluidity and magnetization improved cement hydrate degrees.

Abstract: The magnetic properties of the (Fe_0.53Nd_0.37Al_0.10)₉₆B₄ bulk amorphous alloys annealed in the temperature range of 293-623K for 30 min with and without an external pulsed magnetic field of 5T were studied. The results reveal that the remanence and coercivity of the samples are obviously improved with a pulsed magnetic field when annealed below the Curie temperature of the alloy. The increment of remanence reaches 25.9% for the sample annealed at 523K with a pulsed magnetic field, because of the enhancement of exchange coupling roles between the soft and hard magnetic phases. It provides a new way to improve the magnetic properties of the bulk amorphous alloys produced by pulsed magnetic annealing at temperatures below the Curie point of the alloys.

Abstract: Silicon p-type (100) wafers implanted with Ni, Co, Fe ions to a dose range of 3∙1013–3∙1016 cm-2 have been investigated by means of EPR. The g-factor from dangling bonds of silicon modified by Ni, Co, Fe ion implantation is found to be different from the g-factor of amorphous silicon explained by the change of the local magnetic permeability r. Extreme character of the spin concentration on dose dependence is found, being not typical for silicon.

Abstract: A new method was advanced that the cutter was magnetized using the low Frequency Pulse, and to elaborated the work principle, base on the method of improvement performance of cutter in internal and overseas. The new method was applied at the magnetization of cutter, the performance of magnetization cutter was compared with the un-magnetization using the mensuration test of coefficient of friction and the anti-impact impact test, the influence of cutter was analyzed after the magnetization.

Abstract: The results of experimental investigations of Fe1-xCoxSi crystals in the impurity limit are presented in this article. We made an attempt to study changes of magnetic properties and conductivity in mixed Fe1-xCoxSi crystals in the impurity limit. Magnetoresistance properties are well described in the framework of Kondo model. The presence of Co-subsystem leads to the occurrence of spin-dependent channel in electron scattering conduction.

Abstract: The possibility of obtaining a nanostructured composite in the Ni-Mg-O system by ion-beam sputtering has been investigated. The structural, magnetic and magnetoresistive properties of obtained samples have been investigated in a wide concentration range. The presence of the nanostructure in the obtained samples with Ni nanogranules (2-3 nm) has been confirmed by transmission electron microscopy. There is no observation of any magnetic or magnetoresistive properties at room temperature in the Nix(MgO)100-x composites. These properties were observed at 77 K. The obtained data mean that Curie temperature of the Ni nanogranules is lower then 298 K. This is due to small size of nickel granules and low value of exchange interaction energy in nickel.

Abstract: Structure and magnetic properties of nanoscale [Gd/Ti]n multilayers prepared by rf-sputtering are studied. It is found that the decrease in the Gd layer thickness LGd leads to beginning of the structure transformation in Gd layers from the fine-crystalline to amorphous state when LGd becomes less than 2 nm. The Curie temperature TC decreases as a function of the Gd layer thickness in the same way as in early studied epitaxially grown Gd films, i.e. in case for which the finite-size effect plays most important role. A deviation of the TC(LGd) behaviour at very low LGd from the fit according to the finite-size law is probably caused by the island-like structure of the Gd layers.