This paper reviews the state of art in spin-torque and spin-Hall-effect-driven nano-oscillators. After a brief introduction to underlying physics, authors discuss different implementations these oscillators, their functional properties terms frequency range, output power, phase noise, modulation rates, inherent propensity for mutual synchronization. Finally, potential oscillators wide range applications, from microwave signal sources detectors neuromorphic computation elements, is discussed...

Dissipative solitons have been reported in a wide range of nonlinear systems, but the observation their magnetic analog has experimentally challenging. Using spin transfer torque underneath nanocontact on thin film with perpendicular anisotropy (PMA), we observed generation dissipative droplet and report rich dynamical properties. Micromagnetic simulations identify automodulation frequencies, including oscillatory motion, "spinning," "breather" states. The can be controlled by using both...

Magnetic skyrmions are topologically non-trivial spin textures that manifest themselves as quasiparticles in ferromagnetic thin films or noncentrosymmetric bulk materials. So far attention has focused on stabilized either by the Dzyaloshinskii–Moriya interaction (DMI) dipolar interaction, where latter case excitations known bubble skyrmions. Here we demonstrate existence of a dynamically skyrmion, which exists even when interactions and DMI absent. We establish how such dynamic can be...

A memory effect has been demonstrated in magnetic nanowire arrays. The array the ability to record maximum field that exposed after turned off. origin of is strong dipole interaction among nanowires. Switching distributions nanowires studied with a first-order reversal curve technique elucidate discrepancy between experimental result and theoretical explanation. Based on effect, novel extremely low cost EMP detection scheme proposed.

Abstract Ionic transport in metal/oxide heterostructures offers a highly effective means to tailor material properties via modification of the interfacial characteristics. However, direct observation ionic motion under buried interfaces and demonstration its correlation with physical has been challenging. Using strong oxygen affinity gadolinium, we design model system Gd x Fe 1− /NiCoO bilayer films, where migration is observed manifested controlled positive exchange bias over relatively...

To develop a full understanding of interactions in nanomagnet arrays is persistent challenge, critically impacting their technological acceptance. This paper reports the experimental, numerical and analytical investigation Co nanoellipses using first-order reversal curve (FORC) technique. A mean-field analysis has revealed physical mechanisms giving rise to all observed features: shift non-interacting FORC-ridge at low-HC end off local coercivity HC axis; stretch high-HC without shifting it...

It has been argued that if multiple spin wave modes are competing for the same centrally located energy source, as in a nanocontact torque oscillator, only one mode should survive steady state. Here, experimental conditions necessary coexistence explored. Mode is facilitated by local field asymmetries induced spatially inhomogeneous Oersted field, which leads to physical separation of modes, and further promoted localization at reduced applied angles. Finally, both simulation experiment...

Light polarization rotators and nonreciprocal optical isolators are essential building blocks in photonics technology. These macroscopic passive devices commonly based on magneto-optical Faraday Kerr rotation. Magnetoplasmonics, the combination of magnetism plasmonics, is a promising route to bring these nanoscale. We introduce design rules for highly tunable active magnetoplasmonic elements which we can tailor amplitude sign response over broad spectral range.

Sub-$100\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ nanomagnets not only are technologically important, but also exhibit complex magnetization reversal behaviors as their dimensions comparable to typical magnetic domain wall widths. Here we capture ``fingerprints'' of ${10}^{9}$ Fe nanodots they undergo a single vortex state transition, using first-order curve (FORC) method. As the nanodot size increases from...

Many types of fluorescent nanoparticles have been investigated as alternatives to conventional organic dyes in biochemistry; magnetic beads also a long history biological applications.In this work we apply flame spray pyrolysis order engineer novel type nanoparticle that has both luminescent and properties.The particles cores iron oxide doped with cobalt neodymium shells europium-doped gadolinium (Eu:Gd 2 O 3 ).Measurements by vibrating sample magnetometry showed an overall paramagnetic...

We investigate exchange coupled [Co/Pd]5–NiFe thin films. Due to competition between the in-plane shape anisotropy of NiFe and strong perpendicular magnetic [Co/Pd]5 multilayer, unique configurations are achievable. In particular, we explore out-of-plane magnetization tilt angle layer. Experimental results, based on conventional magnetometry, ferromagnetic resonance, force microscopy, agree well with one-dimensional micromagnetic simulations. find that is highly tunable (0°–60°) over a small...

We demonstrate magnetization auto-oscillations driven by pure spin currents in Hall nano-oscillators based on CoFeB/Pt bilayers. Despite the very low anisotropic magnetoresistance of CoFeB, a substantial microwave signal power can be detected, even at room temperature, indicating that sizable wave amplitude is generated. Spin torque ferromagnetic resonance measurements reveal generated auto-oscillation frequency lies below CoFeB and therefore well described self-localized bullet mode.

Using both broadband ferromagnetic resonance (FMR) spectroscopy and ab initio calculations, we study the magnetodynamic properties of permalloy $(Py,{\mathrm{Ni}}_{80}{\mathrm{Fe}}_{20})$ ${\mathrm{Py}}_{100\ensuremath{-}x}{\mathrm{M}}_{x}$ films with M as platinum (Pt), gold (Au), or silver (Ag). From uniform FMR mode, extract saturation magnetization $({M}_{S})$, damping $(\ensuremath{\alpha})$, inhomogeneous broadening $(\mathrm{\ensuremath{\Delta}}{H}_{0})$; from first perpendicular...

Inverted soft/hard, in contrast to conventional hard/soft, bi-magnetic core/shell nanoparticles of MnxFe3−xO4/FexMn3−xO4 with two different core sizes (7.5 and 11.5 nm) fixed shell thickness (∼0.6 have been synthesized. The structural characterization suggests that the particles an interface a graded composition. magnetic confirms inverted soft/hard structure evidences strong exchange coupling between shell. Moreover, larger soft exhibit smaller coercivities loop shifts, but blocking...

Spin Hall nano-oscillators (SHNOs) are an emerging class of pure spin current driven microwave signal generators. Through the fabrication 20 nm nano-constrictions in Pt/NiFe bilayers, we demonstrate that SHNOs can be scaled down to truly nanoscopic dimensions, with added benefit ultra-low operating currents and improved power conversion efficiency. The lateral confinement leads a strong shape anisotropy field as well additional demagnetizing whose reduction increasing auto-oscillation...

Arrays of nanomagnets have important potential applications as future generation ultrahigh-density patterned magnetic recording media, in which each nanomagnet constitutes a single bit. We introduce powerful technique to identify and quantify reversible irreversible magnetization changes, key challenge characterizing these systems. The experimental protocol consists measuring few families second-order reversal curves along selected profiles the first-order-reversal-curve diagram, then can be...

The carrier type and density in Bi2Se3 single crystals are systematically tuned by introducing a calcium (Ca) dopant. A of ~1x1017 cm-3 which corresponds to ~25 meV the Fermi energy is obtained both n- p-type materials. Electrical transport properties show that insulating behavior achieved low crystals. In addition, band gap reduced effective mass carriers determined.

Magnetic dissipative droplets are localized, strongly nonlinear dynamical modes excited in nanocontact spin valves with perpendicular magnetic anisotropy. These find potential application nanoscale structures for storage and computation, but droplet studies have so far been limited to extended thin films. Here, numerical asymptotic analyses used demonstrate the existence properties of novel solitons confined structures. As a nanowire's width is decreased fixed size at its center, observed...

Abstract Static and dynamic magnetic solitons play a critical role in applied nanomagnetism. Magnetic droplets, type of non-topological dissipative soliton, can be nucleated sustained nanocontact spin-torque oscillators with perpendicular anisotropy free layers. Here, we perform detailed experimental determination the full droplet nucleation boundary current–field plane for wide range sizes demonstrate its excellent agreement an analytical expression originating from stability analysis. Our...

The half-metallic half-Heusler alloy NiMnSb is a promising candidate for applications in spintronic devices due to its low magnetic damping and rich anisotropies. Here we use ferromagnetic resonance (FMR) measurements calculations from first principles investigate how the composition of epitaxially grown influences magnetodynamic properties saturation magnetization $M_S$, Gilbert $\alpha$, exchange stiffness $A$. $M_S$ $A$ are shown have maximum stoichiometric composition, while minimum. We...

Short wavelength exchange-dominated propagating spin waves will enable magnonic devices to operate at higher frequencies and data transmission rates. While giant magnetoresistance (GMR)-based magnetic nanocontacts are efficient injectors of waves, the generated wavelengths 2.6 times nano-contact diameter, electrical signal strength remains too weak for applications. Here we demonstrate nano-contact-based wave generation in tunnel junctions observe large-frequency steps consistent with...

Plasmon rulers are an emerging concept in which the strong near-field coupling of plasmon nanoantenna elements is employed to obtain structural information at nanoscale. Here, we combine nanoplasmonics and nanomagnetism conceptualize a magnetoplasmonic dimer that would be able report nanoscale distances while optimizing its own spatial orientation. The latter constitutes active operation dynamically optimized optical response per measured unit length allows for measurement small large with...

The magnetodynamical properties of nanometer-thick yttrium iron garnet films are studied using ferromagnetic resonance as a function temperature. were grown on gadolinium gallium substrates by pulsed laser deposition. First, we found that the damping coefficient increases temperature for different film thicknesses. Second, two dependencies thickness: at room temperature, thickness decreases, while T = 8 K, find to depend only weakly thickness. We attribute this behavior an enhancement...