Demonstration of a robust magnonic spin wave interferometer

Magnonics is an emerging field dealing with ultralow power consumption logic circuits, in which the flow of spin waves, rather than electric charges, transmits and processes information. Waves, including spin waves, excel at encoding information via their phase using interference. This enables a number of inputs to be processed in one device, which offers the promise of multi-input multi-output logic gates. To realize such an integrated device, it is essential to demonstrate spin wave interferometers using spatially isotropic spin waves with high operational stability. However, spin wave reflection at the waveguide edge has previously limited the stability of interfering waves, precluding the use of isotropic spin waves, i.e., forward volume waves. Here, a spin wave absorber is demonstrated comprising a yttrium iron garnet waveguide partially covered by gold. This device is shown experimentally to be a robust spin wave interferometer using the forward volume mode, with a large ON/OFF isolation value of 13.7 dB even in magnetic fields over 30 Oe

The Comparison of Direct and Indirect Methods for Determining the Magnetocaloric Parameters in the Heusler Alloy Ni50Mn34.8In14.2B

The magnetocaloric properties of the Ni50Mn34.8In14.2B Heusler alloy have been studied by direct measurements of the adiabatic temperature change (ΔTAD(T,H)) and indirectly by magnetization (M(T,H)), differential scanning calorimetry, and specific heat (C(T,H)) measurements. The presence of a first-order ferromagnetic-paramagnetic transition has been detected for Ni50Mn34.8In14.2B at 320 K. The magnetocaloric parameters, i.e., the magnetic entropy change (ΔSM = (2.9-3.2) J/kgK) and the adiabatic temperature change (ΔTAD = (1.3-1.52) K), have been evaluated for ΔH = 1.8 T from CP(T,H) and M(T,H) data and from direct ΔTAD(T,H) measurements. The extracted magnetocaloric parameters are comparable to those of Gd

TM-TE hybridization and tunable refraction in magnetophotonic crystals

In the present work we study the photonic band structure (PBS) and the polarization state of the Bloch eigenmodes of a two-dimensional magnetophotonic crystal (MPC) with square lattice formed from magneto-optically (MO) active cylinders. The refraction of light at the boundary of the MPC is analyzed. We found that both - the PBS and eigenmodes of the MPC - are most significantly altered by the MO activity in the vicinity of the degeneracies. For this case we demonstrated the possibility of an abrupt change in the propagation direction of light by the application of a magnetic field. For the Bloch wave vectors and frequencies corresponding to non-degenerate branches, the alteration of the PBS is shown to be negligible and eigenmodes almost completely coincide with linearly TE- and/or TM-polarized eigenmodes of the non-magnetic photonic crystal.4 page(s

Spectra of the two-dimensional magnetophotonic crystals

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Influence of grain size on the extraordinary Hall effect in magnetic granular alloys

A quantum statistical theory of the influence of grain size on the residual extraordinary Hall effect (EHE) in magnetic metal-insulator granular alloys is presented. It is shown that under certain conditions the quasi-classical size-effect (QSE) can lead to similar behaviors of EHE in metal-metal and metal-insulator alloys. The possible dependences of EHE coefficient on the grain size and the role of the QSE in the giant EHE in nanocomposites are discussed.3 page(s

Solvable model of two-dimensional magnetophotonic crystal

We present theoretical investigation of two-dimensional (2D) magnetophotonic crystal (MPC) with square lattice constructed from two infinite arrays of magnetoactive dielectric sheets at right angle, in the limit of very small sheet thickness and very high dielectric constant, such that their product is constant. Alteration of band structure by external magnetic field is studied. We show that optical activity reduces symmetry of the system and removes degeneracy in the photonic band structure. Also, despite of natural weakness of the magnetooptic activity, dispersion near band edges is found to be strongly sensitive to external magnetic influence.6 page(s

Anomalous Faraday Effect of a system with extraordinary optical transmittance

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Optical properties of nanostructured metallic films containing magnetic media

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The Faraday effect in two-dimensional magneto-photonic crystals

The necessary conditions for the observation of the Faraday effect in 2D magneto-photonic crystals are discussed. It is found. that the Faraday effect may be observed in the directions where any couple of the wave vectors of the harmonics consisting the Bloch waves of TE and TM solutions in zero magnetic field are identical. This direction corresponds neither to Faraday nor to Voigt geometry.4 page(s

Superprism effect in magneto-photonic crystals

6 page(s