Showing 4 results for Magnetization
G. Ahmadpour, A. Ghasemi, E. Paimozd,
Volume 32, Issue 2 (12-2013)
Abstract
The particles of ferrite Ni0.6-xCuxZn0.4Fe2O4, (0-0.5 in step with 0.1) were prepared by the sol-gel method. Sintering process of powders was carried out at 600, 800 and 1000 oC. The effect of the sintering temperature and chemical composition on the structural and magnetic properties of the Cu substituted NiZn ferrite was investigated. EDS analysis and X-ray diffraction patterns confirmed a well defined of single crystal phase with spinel structure. The thermal behavior process and particle size of samples were investigated by thermal analysis TG, DTA techniques and scanning electron microscope, respectively. VSM curves reveal that the sintering temperature and copper content affect saturation magnetization. M ssbauer spectra displays that the copper cations occupy the octahedral sites. With increasing of copper cations, the iron cations immigrate to tetrahedral site, consequently the saturation magnetization decrease.
R. Sobhani, M. Hakimi, M. Khajeh Aminian, P. Kameli,
Volume 35, Issue 3 (12-2016)
Abstract
In this paper, the phase formation process of Mn2.5Ge samples, prepared by mechanical alloying of Mn and Ge metal powders and annealing, has been studied. Results showed that in the milled samples the stable phase is Mn11Ge8 compound with orthorhombic structure and Pnam space group. The value of saturation magnetization increases by increasing milling time from 0.2 up to 1.95 (Am2Kg-1). The remanece of the samples increases by increasing the milling time while the coercivity decreases. Annealing of 15-hour milled sample results in disappearance of Mn and Ge and the formation of new phases of Mn3Ge, Mn5Ge2, Mn5Ge3 and Mn2.3Ge. Mn3Ge is the main phase with Do22 tetragonal structure and I4/mmm space group which is stable and dominant. The enhancement of saturation magnetization in the annealed sample is related to the formation of three new magnetic phases and the increase of coercivity is due to the presence of Mn3Ge compound with tetragonal structure. Studies were replicated on samples made by arc melting method to compare the results and to investigate the effect of the preparation method on phase formation and structural and magnetic properties of the materials. In these samples the saturation value was in range of 0.2 up to 1.95 (Am2Kg-1) depending on preparation methods. Rietveld refinement shows that Mn2.3Ge sample prepared from arc melted under 620oC anealing is single phase. Magnetic analysis of this sample show a saturation magnetization of 5.252(Am2Kg-1) and 0.005 T coercive field.
M. Hakimi, M. Safari,
Volume 38, Issue 1 (6-2019)
Abstract
In this study, the improvement of the magnetic properties of Co2FeSi Heusler compound was followed by the utilization of different experimental synthesizing procedures. Comparing the crystal structure showed that the milled samples had a higher crystalline order than the arc-melted ones. Annealing of the milled sample improved the crystalline order, resulting in the highest saturation magnetization (5/24 μB/F.u.). The difference in the saturation magnetization of the other samples was explained by the core-shell model. Comparison of the various coercivity mechanisms showed that the decrease in the size of crystallites played a key role in the higher value of the milled samples coercivity.
A. H. Kianfar, N. Eskandari, M. A. Arayesh,
Volume 39, Issue 2 (8-2020)
Abstract
In this research the synthesis of [Co(Salen)(PPh3)(H2O)]4[Fe(CN)6] and [Co(Salophen)(PPh3)(H2O)]4[Fe(CN)6] schiff base complexes was reported. Co3O4/CoFe2O4 magnetic nanoparticles were prepared by calcination of these complexes at 500, 550 and 600°C. Precursor complexes were identified by FT-IR and UV-Vis spectroscopy and their thermal behavior was studied via TG/DTA. Nanomagnetic samples were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FT-IR). Magnetic properties of the synthesized nanoparticles were studied using Vibrating Sample Magnetometer (VSM). Magnetic parameters such as saturation magnetization (Ms), remanent magnetization (Mr), coercive field (Hc) and squareness ratio (SQ = Mr/Ms) were determined at room temperature. Stoichiometry and approximate composition of the prepared samples were studied by Electron Diffraction X-ray spectroscopy (EDX). The prepared nanocomposites could be useful in some practical applications due to their high magnetization, good chemical stability and dispersion.
