Tuning the metamagnetic transition in the (Co, Fe)MnP system for magnetocaloric purposes

The inverse magnetocaloric effect taking place at the antiferro-to-ferromagnetic transition of (Co,Fe)MnP phosphides has been characterised by magnetic and direct ?Tad measurements. In Co0.53Fe0.47MnP, entropy change of 1.5?Jkg?1?K?1 and adiabatic temperature change of 0.6?K are found at room temperature for an intermediate field change (?B?=?1...

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...

Thermal spin pumping and magnon-phonon-mediated spin-Seebeck effect

The spin-Seebeck effect (SSE) in ferromagnetic metals and insulators has been investigated systematically by means of the inverse spin-Hall effect (ISHE) in paramagnetic metals. The SSE generates a spin voltage as a result of a temperature gradient in a ferromagnet, which injects a spin current into an attached paramagnetic metal. In the...

Defect evolution during annealing of deformed FeSi alloys studied by positron annihilation spectroscopy

High silicon steel is widely used in electrical appliances. Alloying iron with silicon improves its magnetic performance. A silicon content up to 6.5 wt. % gives excellent magnetic properties such as high saturation magnetization, near zero magnetostriction and low iron loss in high frequencies. Their workability is greatly reduced by the...

Evidence of non-Dzyaloshinskii–Moriya ferromagnetism in epitaxial BiFeO3 films

X-ray diffraction analysis and high-resolution electron microscopy of BiFeO3 films prepared by dc magnetron sputtering on single-crystal LaAlO3 (001) substrates reveal that the films have a highly c-oriented orthorhombic crystalline structure. The magnetic properties of the BiFeO3 films are typical of ensembles of interacting superparamagnetic...

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...

Tunable thermal hysteresis in MnFe(P,Ge) compounds

Structural, magnetic, and magnetocaloric properties of the MnFe(P,Ge) compounds were systematically studied on both bulk alloys and melt-spun ribbons. The experimental results show that the critical behavior of the phase transition can be controlled by changing either the compositions or the annealing conditions. The thermal hysteresis is found...

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...

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...

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...

Reducing the critical switching current in nanoscale spin valves

The current induced magnetization reversal in nanoscale spin valves is a potential alternative to magnetic field switching in magnetic memories. We show that the critical switching current can be decreased by an order of magnitude by strategically distributing the resistances in the magnetically active region of the spin valve. In addition, we...