相关论文: Spin Waves and Switching: The Dynamics of Exchange…
The magnetic properties of Co (<D>=15 nm, <L>=130nm) nanowires are reported. In oxidized wires, we measure large exchange bias fields of the order of 0.1 T below T ~ 100 K. The onset of the exchange bias, between the ferromagnetic core and…
We investigate the spatial distribution of spin orientation in magnetic nanoparticles consisting of hard and soft magnetic layers. The nanoparticles are synthesized in a core / shell spherical morphology where the magnetically hard, high…
Using magnetron sputtering, we produced a series of Co/CoO-MgO nanoparticles on Si(100) substrates. High-resolution transmission electron microscopy (HRTEM) image shows that small isolated Co-clusters (core) covered with CoO (shells) with a…
Some of the main experimental observations related to the occurrence of exchange bias in magnetic systems are reviewed, focusing the attention on the peculiar phenomenology associated to nanoparticles with core/shell structure as compared…
We report exchange bias (EB) in single-phase CoO nanoparticles, where two magnetic phases naturally emerge as the crystallite size decreases from 34.6 to 10.8 nm. The N\'eel temperature (TN) associated with antiferromagnetic ordering…
Coupling at the interface of core/shell magnetic nanoparticles is known to be responsible for the exchange bias (EB) and the relative sizes of core and shell components are supposed to influence the associated phenomenology. In this work,…
Low dissipation data processing with spins is one of the promising directions for future information and communication technologies. Despite a signifcant progress, the available magnonic devices are not broadband yet and have restricted…
Magnetic properties of core-shell cobalt ferrite nanoparticles 15 to 48nm prepared by a sol-gel route have been studied. It is shown that the coercivity follows non-monotonic size dependence varying as 1/d above the maximum (d is the…
The use of magnetic nanowires as memory units is made possible by the exponential divergence of the characteristic time for magnetization reversal at low temperature, but the slow relaxation makes the manipulation of the frozen magnetic…
Neuromorphic computing using spin waves is promising for high-speed nanoscale devices, but the realization of high performance has not yet been achieved. Here we show, using micromagnetic simulations and simplified theory with response…
Using a three-dimensional focused-ion beam lithography process we have fabricated nanopillar devices which show spin transfer torque switching at zero external magnetic fields. Under a small in-plane external bias field, a field-dependent…
We explore the dynamics of spiral spin waves in Permalloy nano-elements with variable aspect ratio of geometric dimensions, and their potential use as improved spin wave emitters with no or little biasing field required. Numerical results…
Nanoscale magnetic systems have been studied extensively in various geometries, such as wires of different cross-sections, arrays of wires, dots, rings, etc. Such systems have interesting physical properties and promising applications in…
Na$_x$CoO$_2$, the parent compound of the recently synthesized superconductor Na$_x$CoO$_2$:$y$H$_2$O, exhibits bulk antiferromagnetic order below $\sim20$ K for 0.75 $\leq x \leq$ 0.9. We have performed neutron scattering experiments in…
Spin waves are promising information carriers which can be used in modern magnonic devices, characterized by higher performance and lower energy consumption than presently used electronic circuits. However, before practical application of…
Using microemulsion methods, CoO-Pt core-shell nanoparticles (NPs), with diameters of nominally 4 nm, were synthesized and characterized by high-resolution transmission electron microscopy (HRTEM) and a suite of x-ray spectroscopies,…
We computed spin wave dispersions of surface-reconstructed Co films on the W(110) surface in the adiabatic approximation. The magnetic exchange interactions are obtained via first-principles electronic structure calculations using the…
Inelastic neutron scattering is used to study the magnetic excitations of the $S=1$ square-lattice antiferromagnet La$_2$NiO$_4$. We find that the spin waves cannot be described by a simple classical (harmonic) Heisenberg model with only…
Antisymmetric exchange interactions lead to non-reciprocal spin-wave propagation. As a result, spin waves confined in a nanostructure are not standing waves; they have a time-dependent phase, because counter-propagating waves of the same…
Using an atomistic spin model, we have simulated spin wave injection and propagation into antiferromagnetic IrMn from an exchange coupled CoFe layer. The spectral characteristics of the exited spin waves have a complex beating behavior…