Practicum in Educational Psychology: comparative analysis between areas of knowledge

In this paper we present the process and results of an investigation in which, after reflecting on the concept of Practicum and, specifically, in the Practicum in Educational Psychology degree taught at the University of A Coruña, an assessment is made taking into account the opinion of the students who have studied this matter, as to the relevance that the planned objectives are given and subsequent achievement of these. The results differ considering the area that the teacher who has tutored belongs to. Methodologicaly, it is a descriptive research, survey type, which involved a significant sample of students in their final year of the degree in the year 2012/13 through a questionnaire which validity (Teaching and content) and reliability (internal consistency) have been properly set (judgment of experts and a pilot experience for the calculation of Cronbach's alpha). The results show that the Practicum program has a good development of most of the objectives, especially those related to skills, where the average of the highest rated goals exceed the rating of 4. This suggests clear lines for innovation and improvement in the areas of conceptual and attitudinal level.

Arquetipo y homofobia en el relato mexicano de temática gay

En este trabajo se pretende analizar cómo autores de diversas generaciones han contribuido al arraigo en el inconsciente colectivo, y en la misma literatura, a fijar valores y juicios predeterminados por los dogmas religiosos e ideologías de las instituciones gubernamentales. Para poder entender la evolución de los patrones del arquetipo y la homofobia, el análisis se realizará tomando en cuenta el orden cronológico en que se suceden los relatos, que van de la Revolución al término de la primera década del nuevo siglo, es decir cien años. También se analizarán los tratamientos estéticos y narrativos en los relatos.

Synthesis of Epitaxial Metal Oxide Nanocrystals via a Phase Separation Approach

Perovskite phase instability of BiMnO3 has been exploited to synthesize epitaxial metal oxide magnetic nanocrystals. Thin film processing conditions are tuned to promote the breakdown of the perovskite precursor into Bi2O3 matrix and magnetic manganese oxide islands. Subsequent cooling in vacuum ensures complete volatization of the Bi2O3, thus leaving behind an array of self-assembled magnetic Mn3O4 nanostructures. Both shape and size can be systematically controlled by the ambient oxygen environments and deposition time.As such, this approach can be extended to any other Bi-based complex ternary oxide system as it primarily hinges on the breakdown of parent Bi-based precursor and subsequent Bi2O3 volatization.

Regular nanodomain vertex arrays in BiFeO3 single crystals

Domain patterns consisting of triangular nanodomains of less than 50 nm size, arranged into long regular vertex arrays separated by stripe domains, were observed by (scanning and high-resolution) transmission electron microscopy and piezoresponse force microscopy in BiFeO3 single crystals grown from solution flux. Piezoresponse force microscopy analysis together with crystallographic analysis by selected area and nanobeam electron diffraction indicate that these patterns consist of ferroelectric 109 degrees domains. A possibility for conserving Kittel's law is discussed in terms of the patterns being confined to the skin layer observed recently on BiFeO3 single crystals.

Epitaxial strain and electric boundary condition effects on the structural and ferroelectric properties of BiFeO3 films

The influence of both compressive and tensile epitaxial strain along with the electrical boundary conditions on the ferroelastic and ferroelectric domain patterns of bismuth ferrite films was studied. BiFeO3 films were grown on SrTiO3(001), DyScO3(110), GdScO3(110), and SmScO3(110) substrates to investigate the effect of room temperature in-plane strain ranging from -1.4% to +0.75%. Piezoresponse force microscopy, transmission electron microscopy, x-ray diffraction measurements, and ferroelectric polarization measurements were performed to study the properties of the films. We show that BiFeO3 films with and without SrRuO3 bottom electrode have different growth mechanisms and that in both cases reduction of the domain variants is possible. Without SrRuO3, stripe domains with reduced variants are formed on all rare earth scandate substrates because of their monoclinic symmetry. In addition, tensile strained films exhibit a rotation of the unit cell with increasing film thickness. On the other side, the presence of SrRuO3 promotes step flow growth of BiFeO3. In case of vicinal SrTiO3 and DyScO3 substrates with high quality SrRuO3 bottom electrode and a low miscut angle of approximate to 0.15 degrees we observed suppression of the formation of certain domain variants. The quite large in-plane misfit of SrRuO3 with GdScO3 and SmScO3 prevents the growth of high quality SrRuO3 films and subsequent domain variants reduction in BiFeO3 on these substrates, when SrRuO3 is used as a bottom electrode.

Epitaxial strain stabilization of ferroelectric phase in PbZrO3 thin films

PbZrO3/SrRuO3/SrTiO3 (100) epitaxial heterostructures with different thickness of the PbZrO3 (PZO) layer (d(PZO) similar to 5-160 nm) were fabricated by pulsed laser deposition. The ultrathin PZO films (d(PZO) <= 10 nm) were found to possess a rhombohedral structure. On increasing the PZO film thickness, a bulk like orthorhombic phase started forming in the film with d(PZO) similar to 22 nm and became abundant in the thicker films. Nanobeam electron diffraction and room-temperature micro-Raman measurements revealed that the stabilization of the rhombohedral phase of PZO could be attributed to the epitaxial strain accommodated by the heterostructures. Room-temperature polarization vs electric field measurements performed on different samples showed characteristic double hysteresis loops of antiferroelectric materials accompanied by a small remnant polarization for the thick PZO films (dPZO >= 50 nm). The remnant polarization increased by reducing the PZO layer thickness, and a ferroelectric like hysteresis loop was observed for the sample with d(PZO) similar to 22 nm. Local ferroelectric properties measured by piezoresponse force microscopy also exhibited a similar thickness-dependent antiferroelectric-ferroelectric transition. Room-temperature electrical properties observed in the PZO thin films in correlation to their structural characteristics suggested that a ferroelectric rhombohedral phase could be stabilized in thin epitaxial PZO films experiencing large interfacial compressive stress.

Direct evidence for cation non-stoichiometry and Cottrell atmospheres around dislocation cores in functional oxide interfaces

Long-range strain fields associated with dislocation cores at an oxide interface are shown to be sufficient enough to create significant variations in the chemical composition around the core (Cottrell atmospheres). Such stress-assisted diffusion of cations towards the cores is proposed to significantly impact the properties of nanoscale functional devices. The figure shows a Z-contrast image of a single dislocation core at an oxide interface.

Labile ferroelastic nanodomains in bilayered ferroelectric thin films

Bilayered Pb(Zr((1-x)),Ti(x))O(3) ferroelectric thin film heterostructures show complex ferroelastic nanodomain patterns. These ferroelastic nanodomains exist only in the upper layer, and hence are able to move under the application of an external electric field. Quantitative analysis reveals an enhanced piezoelectric coefficient of similar to 220 pm V(-1), rendering them attractive for a variety of electromechanical devices.