Anisotropic thermal magnetoresistance for an active control of radiative heat transfer

We predict a huge anisotropic thermal magnetoresistance (ATMR) in the near-field radiative heat transfer between magneto-optical particles when the direction of an external magnetic field is changed with respect to the heat current direction. We illustrate this effect with the case of two InSb spherical particles where we find that the ATMR amplitude can reach values of up to 800% for a magnetic field of 5 T, which is many orders of magnitude larger than its spintronic analogue in electronic devices. This thermomagnetic effect could find broad applications in the fields of ultrafast thermal management as well as magnetic and thermal remote sensing.Comment: 6 pages, 4 figure

Assessment of relevant pinch magnitudes of plasma focus devices based on non-uniform internal distributions of density and temperature

A novel model of the dense z-pinch of a plasma focus (PF) discharge is presented, assuming Gaussian radial distributions of density and temperature inside the pinch. The model is used to assess the temperature, size and lifetime of the focus conflating with available experimental data gathered from discharges in Deuterium performed in the PF PACO with three cathode configurations. The resulting estimations were mean pinch temperatures between 1 and 12 keV, and pinch durations between 10 and 120 ns, each magnitude decreasing and increasing with the filling pressure, respectively. Moreover, the relation found between the mean pinch radius and temperature, ⟨ r p ⟩ and ⟨ T p ⟩ , is consistent with an adiabatic compression given by ⟨ r p ⟩ ⟨ T p ⟩ 3 / 4 ≅ 1.2 − 1.6 mm keV3/4. The estimated width of the Gaussian profile is in agreement with spectroscopic images obtained in another small device.Fil: Giovachini, Ricardo Hernán. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: Barbaglia, Mario Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Abraham Ekeroth, R. M.. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: Clausse, Alejandro. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Magneto-optical Stern-Gerlach forces and nonreciprocal torques on small particles

In this paper we calculate the optical forces and torques caused by the presence of a sizable magneto-optical effect. We find a conservative force proportional to the gradient of the spin density of the light field and an extinction force proportional to the helicity of the light field. The conservative interaction allows for a spin-selective, magnetic field based Stern-Gerlach experiment, capable of differentiating between right and left circular polarizations. We also prove that by using a spinless linearly polarized plane wave, the magneto-optical effect allows for the existence of a permanent nonreciprocal torque, proportional to the intensity of the light field.This research was supported by the Spanish MICINN and European Regional Development Fund (ERDF) through Projects No. FIS2015-69295-C3-1-P, No. FIS2015-69295-C3-3-P, No. PGC2018-095777-B-C21, No. PGC2018-095777-B-C22, the Basque Departamento de Educación through Project No. PI-2016-1-0041, and the María de Maeztu Program No. MDM-2014-037

Size-Dependent Optical Properties of Metallic Nanostructures

Metallic nanostructures are a key component of current and future nanotechnology devices since their individual properties convey the appropriate characteristics for applications in several fields of science and technology. At the nanoscale size, optical properties of metal structures depend not only on the type of material but also on the dimensions and geometry of the structure, suggesting the possibility of tuning optical resonances through appropriate engineering. In this chapter, we will describe methods for calculation of size-dependent optical properties of metal nanostructures and show the successful use of extinction spectroscopy technique to determine the size of nanoparticles (Nps).Fil: Scaffardi, Lucia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Schinca, Daniel Carlos. No especifíca;Fil: Lester, Marcelo Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Videla, Fabian Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Santillán, Jesica María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Abraham, Ricardo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentin