اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMicromagnetic simulations of spinel ferrite particles
150
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
This paper presents the results of simulations of the magnetization field {it ac} response (at $2$ to $12$ GHz) of various submicron ferrite particles (cylindrical dots). The ferrites in the present simulations have the spinel structure, expressed here by M$_{1-n}$Zn$_{n}$Fe$_2$O$_4$ (where M stands for a divalent metal), and the parameters chosen were the following: (a) for $n=0$: M = { Fe, Mn, Co, Ni, Mg, Cu }; (b) for $n=0.1$: M = { Fe, Mg } (mixed ferrites). These runs represent full 3D micromagnetic (one-particle) ferrite simulations. We find evidences of confined spin waves in all simulations, as well as a complex behavior nearby the main resonance peak in the case of the M = { Mg, Cu } ferrites. A comparison of the $n=0$ and $n=0.1$ cases for fixed M reveals a significant change in the spectra in M = Mg ferrites, but only a minor change in the M = Fe case. An additional larger scale simulation of a $3$ by $3$ particle array was performed using similar conditions of the Fe$_3$O$_4$ (magnetite; $n=0$, M = Fe) one-particle simulation. We find that the main resonance peak of the Fe$_3$O$_4$ one-particle simulation is disfigured in the corresponding 3 by 3 particle simulation, indicating the extent to which dipolar interactions are able to affect the main resonance peak in that magnetic compound.
قيم البحث
اقرأ أيضاً
The Raman spectra of single crystals of NiFe2O4 were studied in various scattering configurations in close comparison with the corresponding spectra of Ni0.7Zn0.3Fe2O4 and Fe3O4. The number of experimentally observed Raman modes exceeds significantly
that expected for a normal spinel structure and the polarization properties of most of the Raman lines provide evidence for a microscopic symmetry lower than that given by the Fd-3m space group. We argue that the experimental results can be explained by considering the short range 1:1 ordering of Ni2+ and Fe3+ at the B-sites of inverse spinel structure, most probably of tetragonal P4_122/P4_322 symmetry.
In this paper we show that spinel ferrite nanocrystals (NiFe2O4, and CoFe2O4) can be texturally embedded inside a ZnO matrix by ion implantation and post-annealing. The two kinds of ferrites show different magnetic properties, e.g. coercivity and mag
netization. Anomalous Hall effect and positive magnetoresistance have been observed. Our study suggests a ferrimagnet/semiconductor hybrid system for potential applications in magneto-electronics. This hybrid system can be tuned by selecting different transition metal ions (from Mn to Zn) to obtain various magnetic and electronic properties.
The antivortex is a fundamental magnetization structure which is the topological counterpart of the well-known magnetic vortex. We study here the ultrafast dynamic behavior of an isolated antivortex in a patterned Permalloy thin-film element. Using m
icromagnetic simulations we predict that the antivortex response to an ultrashort external field pulse is characterized by the production of a new antivortex as well as of a temporary vortex, followed by an annihilation process. These processes are complementary to the recently reported response of a vortex and, like for the vortex, lead to the reversal of the orientation of the antivortex core region. In addition to its fundamental interest, this dynamic magnetization process could be used for the generation and propagation of spin waves for novel logical circuits.
We report measurements of magnon spin transport in a spinel ferrite, magnesium aluminum ferrite $mathrm{MgAl_{0.5}Fe_{1.5}O_4}$ (MAFO), which has a substantial in-plane four-fold magnetic anisotropy. We observe spin diffusion lengths $> 0.8$ $mathrm{
mu m}$ at room temperature in 6 nm films, with spin diffusion length 30% longer along the easy axes compared to the hard axes. The sign of this difference is opposite to the effects just of anisotropy in the magnetic energy for a uniform magnetic state. We suggest instead that accounting for anisotropy in exchange stiffness is necessary to explain these results.
The direct liquid injection chemical vapor deposition (DLI-CVD) technique has been used for the growth of cobalt ferrite (CFO) films on (100)-oriented MgAl$_2$O$_4$ (MAO) substrates. Smooth and highly epitaxial cobalt ferrite thin films, with the epi
taxial relationship $mathrm{MAO} (100):[001] parallel mathrm{CFO} (100):[001]$, are obtained under optimized deposition conditions. The films exhibit bulk-like structural and magnetic properties with an out-of-plane lattice constant of $8.370;mathrm{AA}$ and a saturation magnetization of $420;mathrm{kA/m}$ at room temperature. The Raman spectra of films on MgAl$_2$O$_4$ support the fact that the Fe$^{3+}$- and the Co$^{2+}$-ions are distributed in an ordered fashion on the B-site of the inverse spinel structure. The DLI-CVD technique has been extended for the growth of smooth and highly oriented cobalt ferrite thin films on a variety of other substrates, including MgO, and piezoelectric lead magnesium niobate-lead titanate and lead zinc niobate-lead titanate substrates.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
