Ferromagnetic resonance and magnetooptic study of submicron epitaxial Fe(001) stripes

We present a combined magnetooptic and ferromagnetic resonance study of a series of arrays of single-crystalline Fe stripes fabricated by electron beam lithography on epitaxial Au(001)/Fe(001)/MgO(001) films grown by pulsed laser deposition. The analysis of the films revealed a clear fourfold magnetocrystalline anisotropy, with no significant presence of other anisotropy sources. The use of a large series of arrays, with stripe widths between 140 and 1000 nm and separation between them of either 200 nm or 500 nm, allowed studying their magnetization processes and resonance modes as well as the effects of the dipolar interactions on both. The magnetization processes of the stripes were interpreted in terms of a macrospin approximation, with a good agreement between experiments and calculations and negligible influence of the dipolar interactions. The ferromagnetic resonance spectra evidenced two types of resonances linked to bulk oscillation modes, essentially insensitive to the dipolar interactions, and a third one associated with edge-localized oscillations, whose resonance field is strongly dependent on the dipolar interactions. The ability to produce a high quality, controlled series of stripes provided a good opportunity to achieve an agreement between the experiments and calculations, carried out by taking into account just the Fe intrinsic properties and the morphology of the arrays, thus evidencing the relatively small role of other extrinsic factors

New interactions: past and future experiments

In this talk I will review the present status and future perspectives of some popular extensions of the conventional three-neutrino oscillation scenario, from a purely phenomenological point of view. For concreteness I will focus only on three specific scenarios: non-standard neutrino interactions with matters, models with extra sterile neutrinos, and neutrino decay and decoherence.Comment: LaTeX file using jpconf class, 8 pages, 2 tables. Proceedings of the "XXIII International Conference on Neutrino Physics and Astrophysics" (Neutrino 08), Christchurch, New Zealand, May 25-31, 200

Discrepancies between different electron temperature methods: probing the electron energy distribution function

A large panel of diagnostic techniques for the determination of effective electron temperatures Te exists and they rely on different hypothesis/physical phenomena for its measurement. Due to the different underlying assumptions and physical mechanisms used for the calculation of Te, different values of Te may be expected while measuring a plasma in the same conditions, particularly in the case of a non-Maxwellian plasma. To each of these definitions of effective Te, a different effective Te can be defined using the EEDF of the plasma. In this study, we take a low pressure Argon microwave plasma as test case and compare Thomson scattering with line intensity measurements corrected by a collisional radiative model. The results are compared with those obtained from the electron particle balance (ePB)

Dynamic magnetic properties of amorphous Fe80B20 thin films and their relation to interfaces

We present a ferromagnetic resonance study of the dynamic properties of a set of amorphous Fe-B films deposited on Corning Glass® and MgO (001) substrates, either with or without capping. We show that the in plane anisotropy of the MgO grown films contains both uniaxial and biaxial components whereas it is just uniaxial for those grown on glass. The angular dependence of the linewidth strongly differs in terms of symmetry and magnitude depending on the substrate and capping. We discuss the role of the interfaces on the magnetization damping and the generation of the anisotropy. We obtained values of the intrinsic damping parameters comparable to the lowest ones reported for amorphous films of similar compositions

Breaking the configurational anisotropy in Fe single crystal nanomagnets

In this work, we improve the ability to tailor the switching mechanism in nanomagnets by introducing an additional, highly controlled source of anisotropy: magnetocrystalline anisotropy. We analyze the vortex dynamics in single crystal Fe nanotriangles with different orientations of the crystalline axes. By experimental studies and simulation, we show that the angular dependence of the vortex annihilation field springs from the convolution of the crystalline and configurational anisotropies. In contrast, the remanence and the nucleation field present a much simpler behavior controlled by the existence of a single symmetry axis when shape and crystalline orientation are taken into account

Size-selective breaking of the core-shell structure of gallium nanoparticles

This Accepted Manuscript is available for reuse under a CC BY-NC-ND 3.0 licence after the 12 month embargo period provided that all the terms of the licence are adhered toCore-shell gallium nanoparticles (Ga NPs) have recently been proposed as an ultraviolet plasmonic material for different applications but only at room temperature. Here, the thermal stability as a function of the size of the NPs is reported over a wide range of temperatures. We analyze the chemical and structural properties of the oxide shell by x-ray photoelectron spectroscopy and atomic force microscopy. We demonstrate the inverse dependence of the shell breaking temperature with the size of the NPs. Spectroscopic ellipsometry is used for tracking the rupture and its mechanism is systematically investigated by scanning electron microscopy, grazing incidence x-ray diffraction and cathodoluminescence. Taking advantage of the thermal stability of the NPs, we perform complete oxidations that lead to homogenous gallium oxide NPs. Thus, this study set the physical limits of Ga NPs to last at high temperatures, and opens up the possibility to achieve totally oxidized NPs while keeping their sphericityThe research is supported by the MINECO (CTQ2014-53334-C2-2-R, CTQ2017-84309-C2-2-R, MAT2016-80394-R, MAT 2015-65274-R/FEDER and MAT2017-85089-C2-1-R) and Comunidad de Madrid (NANOAVANSENS ref. S2013/MIT-3029) projects. ARC acknowledges Ramón y Cajal program (under contract number RYC-2015-18047). FN acknowledges support from Marie Sklodowska-Curie grant agreement No. 641899 from the European Union´s Horizon 2020 research and innovation programm

Study of the virus vector genus Trichodorus (Diphtherophorina, Trichodoridae) from the Iberian Peninsula, an apparent centre of speciation

Trichodoridae are polyphagous root ectoparasites occurring worldwide. Their major pest status is as virus vector of Tobraviruses. Currently, the family has 102 species classified within 6 genera. The genus Trichodorus is the largest in number of species (56) and predominantly occurs in temperate regions. Traditional morphology-based taxonomy revealed for Europe, a very high species diversity within the Iberian Peninsula, comprising about one fifth of all Trichodoridae described. Characteristic for this fauna is the presence of a morpho-species group within Trichodorus, characterized in males by slightly ventrally curved spicules with a mid-blade constriction with bristles and females with relatively large vaginal sclerotized pieces, quadrangular to triangular in shape. Recent surveys for Trichodoridae in cultivated and natural environments in Southern Spain and compared with the fauna from Portugal revealed four new species of Trichodorus, three of them belonging to this morpho-species group. Molecular analyses based on nuclear ribosomal RNA genes (D2-D3 expansion segments of 28S and partial 18S gene) supported not only the new species but also the morpho-species group as a separate clade. The integrated approach of morphology based taxonomy with molecular and biogeographic data enhanced the accuracy of the observed biodiversity and strengthen the hypothesis of the Iberian Peninsula as a center of speciation.The Society of Nematologists (SON

Hβ Stark broadening in cold plasmas with low electron densities calibrated with Thomson scattering

In the present work Stark broadening measurements have been carried out on low electron density (neb5·1019 m-3) and (relatively) low gas temperature (Tgb1100 K) argon–hydrogen plasma, under low-intermediate pressure conditions (3 mbar–40 mbar). A line fitting procedure is used to separate the effects of the different broadening mechanisms (e.g. Doppler and instrumental broadening) from the Stark broadening. A Stark broadening theory is extrapolated to lower electron density values, below its theoretical validity regime. Thomson scattering measurements are used to calibrate and validate the procedure. The results show in agreement within 20%, what validates the use of this Stark broadening method under such lowdensity conditions. It is also found that Stark broadened profiles cannot be assumed to be purely Lorentzian. Such an assumption would lead to an underestimation of the electron density. This implies that independent information on the gas temperature is needed to find the correct values of ne