Spin waves in yttrium iron garnet (YIG) nano-structures attract increasing attention from the perspective of novel magnon-based data processing applications. For short wavelengths needed small-scale devices, group velocity is directly proportional to spin-wave exchange stiffness constant $\lambda_\mathrm{ex}$. Using wave vector resolved Brillouin Light Scattering (BLS) spectroscopy, we measure $\lambda_\mathrm{ex}$ Ga-substituted YIG thin films and show that it about three times larger than...

Ferromagnetic-ferroelectric composites show strain mediated coupling between the magnetic and electric sub-systems due to magnetostriction piezoelectric effects associated with ferroic phases. We have synthesized core-shell multiferroic nano-composites by functionalizing 10–100 nm barium titanate nickel ferrite nanoparticles complementary groups allowing them self-assemble in presence of a catalyst. The structure was confirmed electron microscopy force microscopy. Evidence for strong...

Ferromagnetic-ferroelectric nanocomposites are of interest for realizing strong strain mediated coupling between electric and magnetic subsystems due to high surface area-to-volume ratio. This report is on the synthesis nickel ferrite (NFO) -barium titanate (BTO) core-shell nano-fibers, field assisted assembly into superstructures, studies magneto-electric (ME) interactions. Electrospinning techniques were used prepare coaxial fibers 0.5-1.5 micron in diameter. The structure annealed was...

An enhancement in the power-conversion-efficiency (η) of a magneto-electric (ME) gyrator has been found by use Mn-substituted nickel zinc ferrite. A trilayer Mn-doped Ni0.8Zn0.2Fe2O3 and Pb(Zr,Ti)O3 η = 85% at low power conditions (∼20 mW/in3) ≥ 80% high (∼5 W/in3). It works close to fundamental electromechanical resonance both direct converse modes. The value is far highest reported so far, which due mechanical quality factor (Qm) magnetostrictive Such highly efficient ME gyrators with...

The coupling between magnetic and electric subsystems in composites of ferromagnetic ferroelectric phases is a product property that facilitated by mechanical strain arises due to magnetostriction the piezoelectric effect constituent phases. Such multiferroic are immense interests for studies on physics electromagnetic use variety applications. Here, we focus magneto-electric (ME) nanocomposites. Particular emphasis core-shell particles coaxial fibers, thin film heterostructures, planar...

Core-shell nanofibers of nickel ferrite and lead zirconate titanate have been synthesized by electrospinning, assembled into superstructure in uniform or non-uniform magnetic fields, characterized terms ferroic order parameters strain mediated magneto-electric (ME) coupling. The core-shell structure was confirmed electron microscopy scanning probe microscopy. Studies on field induced polarization P samples showed a decrease increase P, depending the nature fibers strengthening ME coupling...

Magnetic and dielectric resonances in the sub-terahertz (sub-THz) frequency range are observed pure Al-substituted hexagonal barium ferrite. A resonator based on magnetic excitations has been fabricated its performance characteristics have studied. The possible use of at sub-THz frequencies demonstrated. exhibited a loaded Q-factor 150-330 97-108 GHz. Dielectric single-crystal hexaferrite 75-110 modes excited by circularly polarized electromagnetic waves show nonreciprocal propagation...

This report is on experiments and theory the process of optically stimulated electron population density redistribution in Si-substituted yttrium-iron garnet single crystals at 77 K. It was determined that a photo-induced uniaxial anisotropy field arose YIG:Si sample response to illumination by quasi-linearly polarized laser (λ = 808 nm) leading Fe2+ ions among nonequivalent octahedral sites. The measured variation ferromagnetic resonance (FMR) frequencies X-band. FMR frequency shift...

The observation of dielectric resonance over the frequency range 40-110 GHz in single crystal yttrium iron garnet (YIG) and its magnetic field tuning characteristics are reported. dimensions YIG appropriately chosen order to have occur at a much higher than ferromagnetic avoid any hybrid spin-electromagnetic modes. modes magnetically tunable by 1 with ∼1.75 kOe. required bias fields, however, can be controlled sample (or demagnetization factor Nzz). Theoretical calculations on for reasonable...

We report on the observation of nonlinear magnetoelectric effects at room temperature due to a dc current in ferrimagnetic $M$-type strontium hexaferrite platelets. Utilizing microwave measurement techniques and data shift magnetic mode frequencies, it was found that along hexagonal $c$ axis resulted significant decrease saturation magnetization an increase uniaxial magnetocrystalline anisotropy field. These changes order parameters were directly proportional square applied electric field be...

A continuous reorientation and an abrupt flip to a canted structure in the magnetization of stripe domains are observed under influence electric field yttrium-iron-garnet (YIG)/lead-zirconate-titanate (PZT) bilayer. Magneto-optic techniques have been utilized for observation domain flip. It is found that electrically generated mechanical stress PZT induces uniaxial anisotropy YIG, which large enough initially cause gradual change then transition from out-of-plane orientation state threshold...

Magneto-dielectric effects in self-assembled core-shell nanoparticles of nickel ferrite (NFO) and barium titanate (BTO) have been investigated the millimeter wave frequencies. The nano-composites were synthesized by coating 100 nm 50 with complementary coupling groups allowing them to self-assemble presence a catalyst forming heterogeneous nanocomposites. Magneto-electric (ME) characterization as-assembled particles has carried out measurements relative permittivity ɛr as function frequency...

The converse magnetoelectric effect (CME, $i.e.$ the magnetic response to a static electric field) in ferrite-ferroelectric composites is important for an innovative class of voltage-tunable, high-frequency devices. Technical challenges persist, though, due weak CME coupling, large ferromagnetic-resonance (FMR) linewidth, and need bias field. This study aims overcome those by using single-crystal-like nickel ferrite films exhibiting high magnetostriction narrow FMR linewidth. These present...

The converse magnetoelectric effect is studied by voltage tuning of magnetic resonance in a bilayer (111) yttrium iron garnet (YIG) film and polycrystalline lead zirconate titanate (PZT) when the YIG multi-domain state or under saturation. application DC across PZT manifests as uniaxial anisotropy field results shift resonance. In state, strong with magneto-electric coefficient A = 12 MHz cm/kV. Under saturation, rather weak 2

Abstract This report is on non‐linear magneto‐electric (ME) interactions due to an electric current in single crystal M‐type barium hexaferrite (BaM). The interaction results variations the magnetic order parameters and manifests as tuning of modes a BaM resonator U‐band. A DC along c‐axis ferrite found tune frequency mode by 400 MHz when sample single‐domain state 70 multi‐domain for currents up 20 mA applied voltages 75 V. be linear with power both resonances. shift magnitude higher than...

Single crystal strontium and barium hexaferrites in which Al is substituted for Fe have uniaxial anisotropy fields on the order of 20-30 kOe magnetic excitations at 75-110 GHz. Here, we discuss results investigations magnetostatic forward volume waves dielectric resonances such ferrites. Data mode frequencies were utilized to characterize ferrites terms saturation magnetization, field, gyromagnetic ratio, permittivity, losses. A refined theory with explicit characteristic equation dominant...

Microstripline bandpass filters based on dielectric resonance in polycrystalline nickel ferrite have been designed and characterised for operation at discrete frequencies over 18–36 GHz. The insertion loss of 2–5 dB could be tuned by 0.5–1.3 GHz with a nominal magnetic field.

Resonances are observed in the transmission between two coplanar waveguides coupled by ferromagnetic Co90Ta5Zr5 tubes that wrap around their shorted ends. The resonances assigned to magnetostatic surface waves counter propagate along tube perimeter. We use a model based on an infinite tube, with elliptical cross section of roughly same dimensions as studied structure. Additional theoretical analysis fundamental precession mode experiment is carried out. Periodic boundary conditions dictated...

We report the first study of diverse ferromagnetic thin films via acoustically driven resonance (ADFMR). Angle and field-dependent ADFMR was performed at room temperature on FeCo, FeCoGd, FeGaB, FeCoSiB, which take place Ni film traditionally used in these experiments, with a few exceptions. Surface acoustic wave (SAW) devices are operated three harmonics 0.8-2 GHz frequency range. Each magnetic material has unique signature: FeCo shows standard 4-lobe pattern broad ~100 mT linewidth; FeCoGd...

Abstract This work is on the design, fabrication and characterization of a hexagonal ferrite band-pass filter that can be tuned either with magnetic field or an electric field. The operation based straight-edge Y-type resonator symmetrically coupled to input output microstrip transmission lines. Zn 2 Yfilter demonstrated tunability in 8–12 GHz frequency range by applying in-plane bias H 0 provided built-in permanent magnet. insertion loss 3 dB bandwidth within this band were 8.6 ± 0.4 350 40...

A magnetic field tunable W-band phase shifter based on dielectric resonance in barium hexaferrite has been designed and characterised. shift of 60° with low losses is demonstrated at bias field.

Dielectric resonances in the 37-42 GHz frequency band single crystal barium hexaferrite that occur well below ferromagnetic resonance (FMR) have been investigated. Sample dimensions chosen so mode is lower than spin-wave excitation (in this case, natural domain resonance) frequency. Such dielectric frequencies, being a function of both permittivity and permeability, are magnetic field H tunable. Here, we report on below-FMR magnetodielectric (MDR) axially magnetized hexaferrites their...