Structural and magnetic properties of Sb3+ ions doped Ni-Ba-Co ferrite prepared by sol-gel method
1
Citation
43
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract In the present work, nanocrystalline Sb 3+ ions doped Ni 0.2 Ba 0.1 Co 0.7 Fe 2−x Sb x O 4 (0 ≦ x ≦ 0.1, step by 0.025) ferrites were prepared via sol-gel method. The spinel-phase structure of samples can be confirmed by X-ray diffraction (XRD) patterns. The composition and structure were further studied by fourier transform infrared spectroscopy (FTIR). There were two typical characteristic bands ν 1 and ν 2 related to the stretching vibrations in spinel ferrite in FTIR spectra. Energy dispersive spectrometer (EDS) analyzed the elements of samples. It indicated that the elements of Ni, Ba, Co, Fe, O and Sb existed in the samples. Vibrating sample magnetometer was used to characterize magnetic properties. The saturation magnetization decreased from 57.65 emu/g to 44.50 emu/g with the increasing Sb 3+ ions content, which is attributed to Fe 3+ ions replaced by the Sb 3+ ions. Remanent magnetization and coercivity first decreased and then increased slightly.Keywords:
Nanocrystalline material
Thermally activated magnetization reversal processes become manifest in the dependence of the remanent coercivity on the time during which a magnetic field is applied opposite to the initial magnetization direction. They have important consequences for the long term stability and short time writeability of future high density recording media. In this paper, we report on a new experiment using a contact write/read tester to study the time dependence of the remanent coercivity over more than 10 orders of magnitude (from 6 ns to >60 s). Remanence coercivity and signal decay measurements of a CoPtCr recording medium with 5.5 nm thickness are presented.
Recording media
Magnetization reversal
Stoner–Wohlfarth model
Cite
Citations (78)
In the article, technological condition of Dual phase nanocrystalline Nd 4.5 Fe 76.5- x Ga x Co 1.0 B 18 remanence of bonded magnets was explored, and the more solid base was established by this significative result for the problem of broad interest at home and abroad.
Nanocrystalline material
Base (topology)
Cite
Citations (0)
We propose a method of manipulating the coercivity of anisotropic hydrogenation-disproportionation-desorption-recombination (HDDR) powders to fabricate high-remanence and fine-grained Nd-Fe-B magnets using only hot-pressing without a subsequent hot-deformation process. By reducing the Nd content of anisotropic HDDR precursors such that their coercivity (Hcj) is lowered, the c-axis of each HDDR particle is well-aligned parallel to the direction of the applied magnetic field during the magnetic alignment step. This is because the magnetic repulsive force between adjacent particles, determined by their remanent magnetization, decreases as a result of the low coercivity of each particle. Therefore, after hot-pressing the low-Hcj HDDR powders, a significantly higher remanence (11.2 kG) is achieved in the bulk than that achieved by hot-pressing the high-Hcj HDDR powders (8.2 kG). It is clearly confirmed by the large-scale electron backscatter diffraction (EBSD) analysis that the alignment of the c-axis of each anisotropic HDDR particle in the bulk is improved when low-Hcj HDDR powders are used to fabricate hot-pressed magnets. This coercivity manipulation of HDDR powders can be a helpful method to expand the use of HDDR powders in fabricating anisotropic Nd-Fe-B bulk magnets.
Hot pressing
Cite
Citations (1)
Hysteresis
Stoner–Wohlfarth model
Single domain
Cite
Citations (7)
Cite
Citations (6)
Domain wall (magnetism)
Single domain
Cite
Citations (110)
The aim of this study is to obtain high coercive HDDR powder using additions, without a significant degradation in remanence. In This study, Ga and Dy were chosen as additives. and their role in inducing coercivity will be discussed.
Degradation
Stoner–Wohlfarth model
Cite
Citations (0)
The coercive force and remanence of essentially spherical iron and iron-cobalt alloy particles with diameters from 20 to 3000 Å have been measured at 4°, 76°, and 207°K and compared to the theoretically predicted behavior. The remanence shows a broad, plateau-like maximum while the coercive force has a rather sharp maximum. The maximum of the coercive force occurs at a much larger particle diameter than the maximum of the remanence. It is shown that these essential characteristics follow from the theory. Deviations from theory are seen in the smaller size range and can be accounted for by the distribution of particle sizes. A general treatment of the coercive force of mixtures of thermally stable, high coercive force particles with superparamagnetic and multidomain particles is given.
Superparamagnetism
Particle (ecology)
Single domain
Stoner–Wohlfarth model
Cite
Citations (617)
Texture (cosmology)
Cite
Citations (6)
Mechanically milling SmCo5 powder significantly increases coercivity and remanence ratio by introducing defects; however, these defects can be removed by room-temperature aging, with a resultant decrease in coercivity. A series of (SmCo5)x:C1−x (0.15⩽x⩽1) samples has been fabricated to investigate the effect of C on oxidation protection and magnetic properties. SmCo5 was premilled for 1 h, then added to C powder and milled for times ranging from 15 min to 7 h. X-ray diffraction indicates the presence of crystalline graphite and SmCo5 for milling times ⩽6 h and also shows the presence of fcc Co for milling times >7 h. The magnetic properties are very weakly dependent on milling time after the C addition, which is attributed to the lack of further grain refinement. The saturation magnetization scales linearly with the wt % of SmCo5. Remanence ratios are approximately 0.7 and independent of volume fraction. The maximum coercivity of 16.5 kOe is comparable to the maximum obtained by milling SmCo5 without C. Samples exposed to air for times up to two months show no decrease in coercivity or remanence ratio for x⩽0.70. The addition of C has no detrimental effect on the magnetic properties obtained by milling, except the expected reduction of Ms.
Saturation (graph theory)
Cite
Citations (6)