相关论文: Surface effects on ferromagnetic resonance in magn…
We analyze the absorption of microwaves by the Heisenberg-Ising chain combining exact calculations, based on the integrability of the model, with numerical calculations. Within linear response theory the absorbed intensity is determined by…
Magnetic structures are known to possess magnon excitations confined to their surfaces and interfaces, but these spatially localized modes are often not resolved in spectroscopy experiments. We develop a theory to calculate the confined…
Microscopic model of the interaction of spins with a microwave field in a random-anisotropy magnet has been developed. Numerical results show that microwave absorption occurs in a broad range of frequencies due to the distribution of…
We consider a single spherical nanomagnet and investigate the spatial magnetization profile $\mathbf{m}\left(\mathbf{r}\right)$ in the continuum approach, using the Green's function formalism. The energy of the (many-spin) nanomagnet…
The structure of the electron quantum size levels in spherical nanocrystals is studied in the framework of an eight--band effective mass model at zero and weak magnetic fields. The effect of the nanocrystal surface is modeled through the…
The specific absorption rate (SAR) of a dilute assembly of spherical iron nanoparticles with cubic anisotropy distributed in a viscous liquid is calculated using the solution of stochastic Landau - Lifshitz equation for unit magnetization…
We study the influence of surface anisotropy on the zero-temperature hysteretic properties of a small single-domain magnetic particle, and give an estimation of the anisotropy constant for which deviations from the Stoner-Wohlfarth model…
High fraction of the surface atoms considerably enhances the influence of size and shape on the magnetic and electronic properties of nanoparticles. Shape effects in ferromagnetic nanoparticles are well understood and allow to set and…
Spin non-collinearities in magnetic nanostructures arise from a variety of sources, including structural defects, finite-size effects, boundary or surface effects, Dzyaloshinskii-Moriya exchange coupling, and magnetic vortex formation.…
The influence of surface anisotropy on the magnetization processes of maghemite nanoparticles with ellipsoidal shape is studied by means of Monte Carlo simulations. Radial surface anisotropy is found to favor the formation of hedgehog-like…
The use of a complex ferromagnetic system to manipulate GHz surface acoustic waves is a rich current topic under investigation, but the high-power nonlinear regime is under-explored. We introduce focused surface acoustic waves, which…
Recently observed scaling in the random-anisotropy model of amorphous or sintered ferromagnets is derived by an alternative method and extended for studying the dynamical properties in terms of the Landau-Lifshitz equations for spin blocks.…
In this study we investigate magnetic properties, surface morphology and crystal structure in iron nanoclusters electrodeposited on lightly-doped (100) n-type silicon substrates. Our goal is to investigate the spin injection and detection…
We present a study by ferromagnetic resonance at microwave Q band of two sheets of cobalt nanoparticles obtained by annealing SiO2 layers implanted with cobalt ions. This ex- perimental study is performed as a function of the applied…
We use spin torque ferromagnetic resonance to measure the spectral properties of dipole-exchange spin waves in permalloy nanowires. Our measurements reveal that geometric confinement has a profound effect on the damping of spin waves in the…
We study the interplay between the effects of surface anisotropy and dipolar interactions in monodisperse assemblies of nanomagnets with oriented anisotropy. We derive asymptotic formulas for the assembly magnetization taking account of…
The effect of dipolar interaction and local uniaxial anisotropy on the magnetic response of small spin clusters where spins are located on the vertices of icosahedron, cuboctahedron, tetrahedron and square geometry have been investigated.…
We study analytically and numerically on lattices containing $10^5$ spins, the integral absorption of microwaves by a random-anisotropy magnet, $\int d\omega P(\omega)$. It scales as $D^2_R/J$ on the random-anisotropy strength $D_R$ and the…
We study the effects of the exchange interaction between an adsorbed magnetic atom with easy-axis magnetic anisotropy and the conduction-band electrons from the substrate. We model the system using an anisotropic Kondo model and we compute…
Magnetic nanoparticles of gamma-Fe2O3 coated by organic molecules and suspended in liquid and solid matrices, as well as a non-diluted magnetic fluid have been studied by electron magnetic resonance (EMR) at 77-380 K. Slightly asymmetric…