Micromagnetic simulations of magnetoelastic nanostructures traditionally rely on either the Stoner-Wohlfarth model or Landau-Lifshitz-Gilbert (LLG) model, assuming uniform strain (and/or magnetization). While assumption is reasonable when modeling thin films, this constant approach becomes increasingly inaccurate for smaller in-plane nanoscale structures. This paper presents analytical work intended to significantly improve simulation finite structures by fully coupling LLG with...

Experimental results demonstrate the ability of a surface electrode pattern to produce sufficient in-plane strain in PbZr0.52Ti0.48O3 (PZT) thin film clamped by Si substrate control magnetism 1000 nm diameter Ni ring. The and ring/PZT heterostructure were designed using finite element based micromagnetics code. magnetoelectric heterostructures fabricated on PZT e-beam lithography characterized magnetic force microscopy. Application voltage electrodes moved one “onion” state domain walls....

We simulated the generation and propagation of spin waves (SWs) using two excitation methods, namely, magnetic field voltage induced strain. A fully coupled non-linear magnetoelastic model, combining Landau–Lifshitz-Gilbert with elastodynamic equations, is used to study characteristics SWs in materials. Simulation results show that for frequencies above ferromagnetic resonance (FMR), excited by strain propagate over longer distances compared field. In addition, mediated exhibit loss...

A micromagnetic and elastodynamic finite element model is used to compare the 180° out-of-plane magnetic switching behavior of CoFeB Terfenol-D nanodots with perpendicular easy axes. The systems simulated here consist 50 nm diameter on top a 100 nm-thick PZT (Pby[ZrxTi1-x]O3) thin film, which attached Si substrate. This allows voltage pulses induce strain-mediated in field free environment. Coherent incoherent behaviors are observed both Terfenol nanodots, flipping associated larger or...

This paper presents an analytical model coupling Landau-Lifshitz-Gilbert micromagnetics with elastodynamics and electrostatics to the response of a single domain magnetoelastic nano-element attached piezoelectric thin film (500 nm). The is mounted on Si substrate, globally clamping from in-plane extension or contraction. Local strain transfer element achieved using patterned electrodes. system equations reduced eight coupled partial differential as function voltage (V), magnetic potential ϕ,...

Composite multiferroic systems, consisting of a piezoelectric substrate coupled with ferromagnetic thin film, are great interest from technological point view because they offer path toward the development ultralow power magnetoelectric devices. The key aspect those systems is possibility to control magnetization via an electric field, relying on magneto-elastic coupling at interface between and components. Accordingly, direct measurement both electrically induced magnetic behavior...

Analytical results for a voltage induced 180° perpendicular magnetization switching in single magnetic nanoelement are presented. This is achieved by combining anisotropy due to surface effects with temporally short strain pulse. The angular momentum of the moment its precession response an in-plane effective field strain, causing it overshoot 90° reorientation equilibrium position. Removal at peak switch. process simulated using micromagnetic dynamic approach implemented finite element...

Abstract Strain-coupled multiferroic heterostructures provide a path to energy-efficient, voltage-controlled magnetic nanoscale devices, region where current-based methods of control suffer from Ohmic dissipation. Growing interest in highly magnetoelastic materials, such as Terfenol-D, prompts more accurate understanding their magnetization behavior. To address this need, we simulate the strain-induced change with two modeling methods: commonly used unidirectional model and recently...

Here is studied structure-control systems that can be modeled as an assemblage of beams and nonstructural mass elements augmented by a noncollocated direct output feedback control system. Beam cross-sectional dimensions, masses rotary inertias, controller position velocity gains are treated simultaneously design variables.

Thermochemical energy storage has the potential to reduce cost of concentrating solar thermal power. This paper presents recent advances in ammonia-based thermochemical (TCES), supported by an award from U.S. Dept. Energy SunShot program. Advances have been made three areas: identification promising approaches for underground containment gaseous products dissociation reaction, demonstration that ammonia synthesis can be used generate steam a supercritical-steam Rankine cycle, and preliminary...

Abstract A control‐augmented structural synthesis methodology is presented in which actuator and sensor placement treated terms of (0, 1) variables. Structural member sizes control variables are simultaneously as design multiobjective utopian approach used to obtain a compromise solution for inherently conflicting objective functions such mass, effort number actuators. Constraints imposed on natural frequencies, peak transient displacements accelerations, forces dynamic stability well...

Ferromagnetic resonance and spin waves have been used in miniaturized devices for rf microwave applications, but large magnetic bias fields are required the high frequencies at which most satellites operate, example. Exploiting perpendicular standing an innovative way, authors excite spin-wave above 20 GHz with below 100 Oe, can be realized small, lightweight permanent magnets, or electromagnets current sources that would not require cooling.

This study provides numerical simulations for deterministic 360° magnetization rotation of the transverse domain walls in a nickel nano-ring (outer diameter: 500 nm, inner 300 and thickness: 10 nm) on lead zirconate titanate (Pb[ZrxTi1-x]O3 0 < x 1) (PZT) thin film (500 deposited onto Si substrate with surface patterned electrodes. Two alternative electrode architectures are studied, namely, 4-electrode 6-electrode configuration. The configuration relies dynamics to produce an...

A 400 MHz magnetoelectric (ME) Lamb wave antenna design to function in the medical implant communication service band is proposed. The employs a heterostructure of piezoelectric and magnetostrictive membranes acoustically excite standing shear bulk radiate as magnetic dipole. Multiphysics finite element analysis simulations are performed for transmission reception modes. In these simulations, three aspects investigated: piezoelectricity, micromagnetic precession, dipole radiation. An...

Designing and implementing means of locally trapping magnetic beads understanding the factors underlying bead capture force are important steps toward advancing capture-release process particles for biological applications. In particular, capturing magnetically labeled cells using microstructures with perpendicular anisotropy (PMA) will enable an approach to cell manipulation emerging lab-on-a-chip devices. Here, a Co (0.2 nm)/Ni (0.4 nm) multilayered structure was designed exhibit strong...

In this paper, a fully coupled analytical model between elastodynamics with micromagnetics is used to study the switching energies using voltage induced mechanical bending of magnetoelastic bit. The bit consists single domain nano-ellipse deposited on thin film piezoelectric (500 nm) attached thick substrate (0.5 mm) patterned electrodes underneath nano-dot. A applied produces out plane deformation moments in modifying magnetic anisotropy. To minimize energy, two design stages are used....

The magnetoelectric behavior of epitaxial Fe-Ga microstructures on top a (001)-oriented PMN-PT piezoelectric substrate is imaged with magnetic X-ray microscopy. Additionally, the micron-scale strain distribution in characterized by microdiffraction and examined respect to results switching. reorientation found be strongly correlated size, shape, crystallographic orientation microstructures. In case square-shaped structures, size dictates influence both initialization ground state during...

Piezoelectric resonators have been generally modeled with the electrostatic approximation, which does not predict any electromagnetic (EM) wave behavior. In this research, we develop and validate a fully coupled finite-element (FE) model to study interaction between elastodynamics electrodynamics. We simulate EM radiation from vibrating piezoelectric resonator excited by harmonic shears via d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Abstract A method to efficiently solve the problem of minimum weight design plane and space trusses with discrete or mixed variables is developed. The can also be applied continuous variables. original formulation leads a non‐linear constrained minimization inequality constraints, which solved by means sequence approximate problems using dual techniques. In space, objective function maximized, depends on variables, concave has first second order discontinuities. addition, constraints deal...

A model is developed to correlate the effects of size on thermodynamic efficiency for a nickel-based multiferroic thermomagnetic generator device. Three existing models are combined in order estimate this correlation, they (1) relations, (2) ferromagnetic transition behavior, and (3) bond-order length strength correlation. At smallest considered, monolayer nickel atoms shows reduction Curie temperature from its bulk value Tc,Bulk=630 K Tc,ML=240 K. This difference analytically shown affect...

Precise control and manipulation of nano-beads have various applications, e.g. cell sorter, 3D printing nano-motors. In this paper we present an approach in which use voltage on a piezolecetric substrate order to reorient the magnetization nano-disk. turn drives dynamic nano-beads. This is energy efficient method motion since only applied substrate. The mechanism consists Ni disk three pairs surface electrodes placed PZT By controlling different electrodes, will rotate with constant angular...

In this paper we analyze the 3D modes of a linear homogeneous magnetoelectroelastic (MEE) material reduced to magnetoelectric (ME) constitutive form.This allows convenient examination predominately electromagnetic behavior in mechanically coupled MEE system.We find that are strongly influenced by mechanical coupling present system.A number papers refer cross-coupling laminated piezoelectric and piezomagnetic materials as materials.We discuss here composite systems relations need reflect...

A new approximation for peak transient dynamic displacements is presented. This based on modal analysis and valid general damped structures, which includes the case of actively controlled structures. Intermediate design variable intermediate response quantity concepts are used to enhance accuracy approximation. When this high-quality within context approach synthesis, overall efficiency process expected be improved by reducing number complete analyses required convergence. Numerical results...