Dzyaloshinsky-Moriya antisymmetric exchange coupling in cuprates: Oxygen effects

We revisit a problem of Dzyaloshinsky-Moriya antisymmetric exchange coupling for a single bond in cuprates specifying the local spin-orbital contributions to Dzyaloshinsky vector focusing on the oxygen term. The Dzyaloshinsky vector and respective weak ferromagnetic moment is shown to be a superposition of comparable and, sometimes, competing local Cu and O contributions. The intermediate oxygen $^{17}$O Knight shift is shown to be an effective tool to inspect the effects of Dzyaloshinsky-Moriya coupling in an external magnetic field. We predict the effect of $strong$ oxygen weak antiferromagnetism in edge-shared CuO$_2$ chains due to uncompensated oxygen Dzyaloshinsky vectors. Finally, we revisit the effects of symmetric spin anisotropy, in particular, those directly induced by Dzyaloshinsky-Moriya coupling.Comment: 12 pages, 2 figures, submitted to JET

[Introduction] The future of childhood studies and Children & Society

No description supplie

Young masculinities across five European countries : performing under pressure

© 2019 Informa UK Limited, trading as Taylor & Francis Group. We present an analysis of young masculinities based on young peoples’ perspectives derived from a project on sexual bullying. Our qualitative data are based on 41 focus groups with 253 young people (male and female) aged 13–18 across five European countries (Bulgaria, Italy, Latvia, Slovenia and England) as well as questionnaire responses. The data were analysed using thematic analysis (Braun, V., and V. Clarke. 2006. “Using Thematic Analysis in Psychology.” Qualitative Research in Psychology 3 (2): 77–101). Our analysis pointed to the prevalence of sexist and homophobic behaviours among young men, who were themselves concerned with their ‘masculine’ reputations by appearing physically tough, (hetero)sexually active and emotionally closed. The young women in our sample also depicted many young men as immature, naïve and superficial. At the same time, the young men were portrayed as more calm, rational and resilient compared to their female counterparts, with young men insisting that any ‘problematic’ or ‘bullying’ behaviour amounted to harmless fun. Our analysis suggests that young men are performing gender and sexuality under the influence of conventional norms which prioritise homosociality, humour and status, which shy away from challenging sexist or homophobic practices, and which inhibit reporting themselves as victims of bullying. The implications for young masculinities and social change are discussed

Density functional electronic spectrum of the CuO−6−10Cu O_{-6}^{-10} cluster and possible local Jahn-Teller distorsions in the La-Ba-Cu-O superconductor

We present a density functional theory (DFT) calculation in the generalized gradient approximation to study the possibility for the existence of Jahn-Teller (JT) or pseudo Jahn-Teller (PJT) type local distortions in the La-Ba-Cu-O superconducting system. We performed the calculation and correspondingly group theory classification of the electronic ground state of the CuO${_{6}}^{-10}$ elongated octahedra cluster, immersed in a background simulating the superconductor. Part of the motivation to do this study is that the origin of the apical deformation of the CuO${_{6}}^{-10}$ cluster is not due to a pure JT effect, having therefore a non {\it a priori} condition to remove the degeneracy of the electronic ground state of the parent regular octahedron. We present a comparative analysis of the symmetry classified electron spectrum with previously reported results using unrestricted Hartree-Fock calculations (UHF). Both the DFT and UHF calculations produced a non degenerate electronic ground state, not having therefore the necessary condition for a pure JT effect. However, the appearance of a degenerate E$_{g}$ state near to the highest occupied molecular orbital in the DFT calculation, suggests the possibility for a PJT effect responsible for a local distortion of the oxidized CuO$_{6}^{-9}$ cluster.Comment: 12 pages, 3 figures, submitted to International Journal of Modern Physics B (IJMPB

The problem of gender categorisation: addressing dilemmas past and present in gender and education research

Developments in the field of gender theory as applied to education since the 1970s are briefly reviewed in order to highlight key challenges and debates around gender categorisation and identification in gender and education. We argue that conundrums of categorisation have haunted, and continue to haunt, the field of gender theory, and empirical applications (such as the case of education) in particular. We explain how we have attempted to address some of the conundrums arising in our own theoretical work, and analyse remaining challenges that we feel the field of education needs to address in order to advance theoretically. Identifying two key tensions underpinning this empirical dilemma of gender categorisation – the tension between agency and determinism in gender identification, and that between gender deconstruction and gender analysis – we seek to weave a path through some of these complex debates, and to indicate ways in which they may be addressed in future work. We argue that in order to avoid essentialism and reification of gender distinction, we need to apply a ‘three-fold’ analysis that incorporates three different elements in our categorisation of gender: spectator perspective; respondent perspective and social context

Sporting equality and gender neutrality in korfball

This paper explores the extent to which korfball can be considered egalitarian. The intention of this research was to use ethnographic methods to discover the ways in which gender was negotiated, challenged or recreated in a junior korfball setting and examine to what extent korfball provided an opportunity to promote gender egalitarianism. Analysis of the data incorporated a broad Foucauldian lens and subsequently revealed that sex equality was visible to some degree in the junior korfball space. From observations and interviews it was clear that male domination was rarely evident when considering the vocal nature of the game, the physicality and competitiveness of players, or their general ability and skill, yet when interviewed players still constructed gender in traditional ways. Nevertheless, korfball was seen to offer a space where there were possibilities for sporting equality although the influence that the sport had beyond the court was less apparent