Exchange magnetic field torques in YIG/Pt bilayers observed by the spin-Hall magnetoresistance

The effective field torque of an yttrium-iron-garnet (YIG) film on the spin accumulation in an attached platinum (Pt) film is measured by the spin-Hall magnetoresistance (SMR). As a result, the magnetization direction of a ferromagnetic insulating layer can be measured electrically. Experimental transverse and longitudinal resistances are well...

Evidence of the Griffiths phase in multiferroic BiMnO3 and BiFe0.5Mn0.5O3 films

Microstructure and magnetic properties of BiMnO3 and BiFe0.5Mn0.5O3 films, prepared by rf magnetron sputtering on LaAlO3 (001) single-crystalline substrate, are investigated. The selected-area electron diffraction analysis allows us to identify the crystal structure of the BiMnO3 film as orthorhombic, while the BiFe0.5Mn0.5O3 film has a...

Barnett effect in thin magnetic films and nanostructures

The Barnett effect refers to the magnetization induced by rotation of a demagnetized ferromagnet. We describe the location and stability of stationary states in rotating nanostructures using the Landau–Lifshitz–Gilbert equation. The conditions for an experimental observation of the Barnett effect in different materials and sample geometries are...

Magnetic materials and devices for integrated radio-frequency electronics

The effect of a neighboring metal layer on the high-frequency characteristics of a thin magnetic stripe

The spin-wave spectrum of a ferromagnetic stripe placed above a metallic layer with finite conductivity is studied by using the magnetostatic Green’s function formalism. It is shown that the frequency and linewidth of the resonances are uniquely determined by complex, mode-dependent demagnetization factors. The formalism developed is used to...

Nonreciprocal spin wave spectroscopy of thin Ni–Fe stripes

The authors report on the observation of nonreciprocal spin wave propagation in a thin ( ? 200?nm) patterned Ni–Fe stripe. The spin wave transmission spectrum is measured using a pair of microstrip lines as antennas. The nonreciprocity of surface wave dispersion brought about by an adjacent aluminum ground leads to a nonreciprocal coupling of...

Electrically detected ferromagnetic resonance

We study the magnetoresistance properties of thin ferromagnetic CrO2 and Fe3O4 films under microwave irradiation. Both the sheet resistance ? and the Hall voltage VHall characteristically change when a ferromagnetic resonance (FMR) occurs in the film. The electrically detected ferromagnetic resonance (EDFMR) signals closely match the...

High-resistivity nanogranular Co–Al–O films for high-frequency applications

This work presents a series of high-resistivity nanogranular Co–Al–O films with maximum resistivity of ? 110?m??cm. The films were deposited using pulsed dc reactive sputtering of a Co72Al28 target in an oxygen/argon ambient. The samples were characterized by scanning electron microscopy (SEM), M-H loop measurements, and s-parameter measurements...

Shape-induced ultrahigh magnetic anisotropy and ferromagnetic resonance frequency of micropatterned thin Permalloy films

Magnetic anisotropy Hk>200?Oe was observed from bar-shaped Permalloy strips. The film was deposited on sputtered Cr seed layer by electroplating under ? 800?Oe external magnetic field. Tiny degradation of Hk was observed after 30 min postannealing at 400?°C in the absence of external magnetic field. The Permalloy strip with in-plane aspect ratio...

10?GHz bandstop microstrip filter using excitation of magnetostatic surface wave in a patterned Ni78Fe22 ferromagnetic film

Various microstrips with a ferromagnetic core were designed and fabricated on a silicon substrate. The core was formed by a 0.5-?m-thick Ni78Fe22 film, patterned into rectangular prisms. Measurement results for attenuation constant versus frequency show a peak value of ? 50?dB/cm around 10?GHz. Electromagnetic simulations show that the...

Enhancing the charge ordering temperature in thin films of Pr0.5Ca0.5MnO3 by strain

We report the effects of biaxial strain on the charge ordering temperature Tco of the mixed-valent manganite perovskite oxide Pr0.5Ca0.5MnO3. Thin films were grown on SrTiO3, which has a 1.3% larger in-plane lattice parameter. Other substrates were used for comparison. Transport measurements combined with data from electron microscopy show that...

Magnetic properties of electroplated nano/microgranular NiFe thin films for rf application

A granular NiFe thin film with large in-plane magnetic anisotropy and high ferromagnetic-resonance frequency developed for radio-frequency integrated circuit (IC) applications is presented. During the deposition, three-dimensional (3D) growth occurs, yielding NiFe grains (? ? 1.0??m). Nanonuclei (? ? 30–50?nm) are observed in single NiFe grains...

Magnetovibrational coupling in small cantilevers

A nanomagnetomechanical system consisting of a cantilever and a thin magnetic film is predicted to display magnetovibrational modes, which should enable applications for sensors and actuators. The “polaritonic” modes can be detected by line splittings in ferromagnetic resonance spectra.

Spin-torque transistor

A magnetoelectronic thin-film transistor is proposed that can display negative differential resistance and gain. The working principle is the modulation of the soure–drain current in a spin valve by the magnetization of a third electrode, which is rotated by the spin-torque created by a control spin valve. The device can operate at room...

Polarized Neutron Reflectometry on Thin Magnetic Films, Gepolariseerde Neutronen Reflectometrie aan Dunne Magnetische Lagen