Obtaining Au thin films in atmosphere of reactive nitrogen through magnetron sputtering

4d and 5d series of the transition metals are used to the obtaining nitrides metallic, due to the synthesis of PtN, AgN and AuN in the last years. Different nitrides are obtained in the Plasma Assisted Physics Vapour Deposition system, due to its ionization energy which is necessary for their formation. In this paper a Magnetron Sputtering system was used to obtain Au thin films on Si wafers in Nitrogen atmosphere. The substrate temperature was varied between 500 to 950°C. The samples obtained at high temperatures (>500°C) show Au, Si and N elements, as it is corroborated in the narrow spectrum obtained for X-Ray Photoelectron Spectroscopy; besides the competition of orientation crystallographic texture between (111) and (311) directions was present in the X-Ray Diffraction analysis to the sample heated at 950°C

Amalgamated products and properly 3-realizable groups

In this paper, we show that the class of all properly 3-realizable groups is closed under amalgamated free products (and HNN-extensions) over finite groups. We recall that $G$ is said to be properly 3-realizable if there exists a compact 2-polyhedron $K$ with $\pi_1(K) \cong G$ and whose universal cover $\tilde{K}$ has the proper homotopy type of a 3-manifold (with boundary).Comment: J. Pure Appl. Alg., to appea

Comment on "Lattice Gluon and Ghost Propagators, and the Strong Coupling in Pure SU(3)SU(3) Yang-Mills Theory: Finite Lattice Spacing and Volume Effects"

The authors of ref. Phys.Rev. D94 (2016) no.1, 014502 reported about a careful analysis of the impact of lattice artifacts on the $SU(3)$ gauge-field propagators. In particular, they found that the low-momentum behavior of the renormalized propagators depends on the lattice bare coupling and interpreted this fact as the result of it being affected by finite lattice spacing artifacts. We do not share this interpretation and present here a different and more suitable explanation for these results

Are the low-momentum gluon correlations semiclassically determined?

We argue that low-energy gluodynamics can be explained in terms of semi-classical Yang-Mills solutions by demonstrating that lattice gluon correlation functions fit to instanton liquid predictions for low energies and, after cooling, in the whole range.Comment: 4 pages, revtex

Coupled magnetic and elastic properties in LaPr(CaSr)MnO manganites

We investigate a series of manganese oxides, the La0.225Pr0.4(Ca1-xSrx)0.375MnO3 system. The x = 0 sample is a prototype compound for the study of phase separation in manganites, where ferromagnetic and charge ordered antiferromagnetic phases coexist. Replacing Ca2+ by Sr2+ gradually turns the system into a homogeneous ferromagnet. Our results show that the material structure plays a major role in the observed magnetic properties. On cooling, at temperatures below 100 K, a strong contraction of the lattice is followed by an increase in the magnetization. This is observed both through thermal expansion and magnetostriction measurements, providing distinct evidence of magneto-elastic coupling in these phase separated compounds

Magnetocaloric effect in manganites: metamagnetic transitions for magnetic refrigeration

We present a study of the magnetocaloric effect in La5/8-yPryCa3/8MnO3 (y=0.3) and Pr0.5Ca0.09Sr0.41MnO3 manganites. The low temperature state of both ystems is the result of a competition between the antiferromagnetic and ferromagnetic phases. The samples display magnetocaloric effect evidenced in an adiabatic temperature change during a metamagnetic transition from an antiferromagnetic to a ferromagnetic phase . As additional features, La5/8-yPryCa3/8MnO3 exhibits phase separation characterized by the coexistence of antiferromagnetic and ferromagnetic phases and Pr0.5Ca0.09Sr0.41MnO3 displays inverse magnetocaloric effect in which temperature decreases while applying an external magnetic field. In both cases, a significant part of the magnetocaloric effect appears from non-reversible processes. As the traditional thermodynamic description of the effect usually deals with reversible transitions, we developed an alternative way to calculate the adiabatic temperature change in terms of the change of the relative ferromagnetic fraction induced by magnetic field. To evaluate our model, we performed direct measurement of the sample's adiabatic temperature change by means of a differential thermal analysis. An excellent agreement has been obtained between experimental and calculated data. These results show that metamagnetic transition in manganites play an important role in the study of magnetic refrigeration.Comment: Acepted to be published in Applied Physics Letter

Weak Z\mathcal Z-structures and one-relator groups

Motivated by the notion of boundary for hyperbolic and $CAT(0)$ groups, M. Bestvina in "Local Homology Properties of Boundaries of Groups" introduced the notion of a (weak) $\mathcal Z$-structure and (weak) $\mathcal Z$-boundary for a group $G$ of type $\mathcal F$ (i.e., having a finite $K(G,1)$ complex), with implications concerning the Novikov conjecture for $G$. Since then, some classes of groups have been shown to admit a weak $\mathcal Z$-structure (see "Weak $\mathcal Z$-structures for some classes of groups" by C.R. Guilbault for example), but the question whether or not every group of type $\mathcal F$ admits such a structure remains open. In this paper, we show that every torsion free one-relator group admits a weak $\mathcal Z$-structure, by showing that they are all properly aspherical at infinity; moreover, in the $1$-ended case the corresponding weak $\mathcal Z$-boundary has the shape of either a circle or a Hawaiian earring depending on whether the group is a virtually surface group or not. Finally, we extend this result to a wider class of groups still satisfying a Freiheitssatz property

Trauma exposure during immigration: important considerations for professionals working with Latina immigrant populations

Presentation made at Latinos in the Heartland (11th : 2013 : Columbia, Mo.) and published in the annual conference proceedings.Latina immigrants represent a population that has been historically under-served an exploited (Ojeda, Flores, Meza & Morales, 2011). Therefore, it is the responsibility of professionals that work with this vulnerable group to not further victimize or misuse research participants. This exploratory paper summarizes available literature relating to trauma experienced by Latina immigrants during migration and provides guidance for researchers and other professionals who work with Latina immigrant populations. It is important to note here, however, that the authors of this paper are not suggesting that severe trauma is necessarily a part of all Latina immigrant migration experiences. Rather, that they emphasize the point that this population is especially vulnerable. It is important that researchers and professionals working with Latina immigrants consider this topic