Divergence of the dielectric constant in ultrathin granular metal films near the percolation threshold

We report on the electronic and optical properties of ultrathin granular films. We demonstrate that the static dielectric constant increases with thickness in the dielectric regime and diverges at the critical thickness, as predicted by classical percolation theory. However, for thicker samples, the dc conductivity does not obey scaling laws due to the presence of tunneling conduction. In this region the dielectric constant is positive, and the electronic transport is not metallic but can be described by Jonscher's universal power law, even though there is a Drude-like response indicating the presence of free charge carriers. Only for thicker films when the dielectric constant becomes negative is there metallic conduction

Multimode Quantitative Scanning Microwave Microscopy of In Situ Grown Epitaxial Ba\u3csub\u3e1-x\u3c/sub\u3eSr\u3csub\u3ex\u3c/sub\u3eTiO\u3csub\u3e3\u3c/sub\u3e Composition Spreads

We have performed variable-temperature multimode quantitative microwavemicroscopy of in situepitaxial Ba1−xSrxTiO3 thin-film composition spreads fabricated on (100) LaA1O3 substrates. Dielectric properties were mapped as a function of continuously varying composition from BaTiO3 to SrTiO3. We have demonstrated nondestructive temperature-dependent dielectric characterization of local thin-film regions. Measurements are simultaneously taken at multiple resonant frequencies of the microscope cavity. The multimode measurements allow frequency dispersion studies. We observe strong composition-dependent dielectric relaxation in Ba1−xSrxTiO3 at microwave frequencies

High Temperature Ferromagnetism with Giant Magnetic Moment in Transparent Co-doped SnO2-d

Occurrence of room temperature ferromagnetism is demonstrated in pulsed laser deposited thin films of Sn1-xCoxO2-d (x<0.3). Interestingly, films of Sn0.95Co0.05O2-d grown on R-plane sapphire not only exhibit ferromagnetism with a Curie temperature close to 650 K, but also a giant magnetic moment of about 7 Bohr-Magneton/Co, not yet reported in any diluted magnetic semiconductor system. The films are semiconducting and optically highly transparent.Comment: 12 pages, 4 figure

Pregnancy and childbirth in English prisons : institutional ignominy and the pains of imprisonment

© 2020 The Authors. Sociology of Health & Illness published by John Wiley & Sons Ltd on behalf of Foundation for SHIL.With a prison population of approximately 9000 women in England, it is estimated that approximately 600 pregnancies and 100 births occur annually. Despite an extensive literature on the sociology of reproduction, pregnancy and childbirth among women prisoners is under‐researched. This article reports an ethnographic study in three English prisons undertaken in 2015‐2016, including interviews with 22 prisoners, six women released from prison and 10 staff members. Pregnant prisoners experience numerous additional difficulties in prison including the ambiguous status of a pregnant prisoner, physical aspects of pregnancy and the degradation of the handcuffed or chained prisoner during visits to the more public setting of hospital. This article draws on Erving Goffman's concepts of closed institutions, dramaturgy and mortification of self, Crewe et al.'s work on the gendered pains of imprisonment and Crawley's notion of ‘institutional thoughtlessness’, and proposes a new concept of institutional ignominy to understand the embodied situation of the pregnant prisoner.Peer reviewe

Modification of the Landau-Lifshitz Equation in the Presence of a Spin-Polarized Current in CMR and GMR Materials

We derive a continuum equation for the magnetization of a conducting ferromagnet in the presence of a spin-polarized current. Current effects enter in the form of a topological term in the Landau-Lifshitz equation . In the stationary situation the problem maps onto the motion of a classical charged particle in the field of a magnetic monopole. The spatial dependence of the magnetization is calculated for a one-dimensional geometry and suggestions for experimental observation are made. We also consider time-dependent solutions and predict a spin-wave instability for large currents.Comment: 4 two-column pages in RevTex, 3 ps-figure

The interview as narrative ethnography : seeking and shaping connections in qualitative research.

Acts of counter-subjectification in qualitative research are always present but are often submerged in accounts that seek to locate the power of subjectification entirely with the researcher. This is particularly so when talking to people about sensitive issues. Based on an interview-based study of infertility and reproductive disruption among British Pakistanis in Northeast England, we explore how we, as researchers, sought and were drawn into various kinds of connections with the study participants; connections that were actively and performatively constructed through time. The three of us that conducted interviews are all female academics with Ph.Ds in anthropology, but thereafter our backgrounds, life stories and experiences diverge in ways that intersected with those of our informants in complex and shifting ways. We describe how these processes shaped the production of narrative accounts and consider some of the associated analytical and ethical implications

Giant positive magnetoresistance in metallic VOx thin films

We report on giant positive magnetoresistance effect observed in VOx thin films, epitaxially grown on SrTiO3 substrate. The MR effect depends strongly on temperature and oxygen content and is anisotropic. At low temperatures its magnitude reaches 70% in a magnetic field of 5 T. Strong electron-electron interactions in the presence of strong disorder may qualitatively explain the results. An alternative explanation, related to a possible magnetic instability, is also discussed.Comment: 4 pages, 5 figures included in the text, references update

Translanguaging and Public Service Encounters: Language Learning in the Library

This article explores the information desk of a city library as a site for language learning. Using a linguistic ethnographic approach, the interactions between a customer experience and information assistant and the many library users who approach her information desk were analysed. Findings are that, in addition to providing information about library resources, information desks are sites at which bits and pieces of different languages are taught and learned. Such language teaching and learning episodes created interactions of inclusion and welcome that went far beyond purely transactional information. Rather, language‐related episodes created moments of human contact and engagement, which were upheld through the translanguaging practices of interactants, the disposition and workplace competence of library staff, and the spatial ecology of the information desk. Furthermore, the article contributes to ongoing theoretical debates about translanguaging by noting that normativity and pressure toward uniformity are as much a part of languaging processes as creativity and flexibility. Our definition of translanguaging recognises the opposing pull of centrifugal and centripetal forces. The article ends by asking what schools, and language education, might learn from public libraries in creating arenas that maintain communitarianism, diversity of expression, and the development of civic skills

Translanguaging and translation: the construction of social difference across city spaces

This paper considers the construction of social difference in the interactions of a couple as they communicate at home and work, with one another, their colleagues, and strangers in a superdiverse English city. In our linguistic ethnographic approach we observed, wrote field notes, audio-recorded key participants, took photographs, made video-recordings, and conducted interviews. We documented the role translanguaging and translation played and showed how these social practices varied across the city’s spatial realms as different kinds of relationships are brought into play. While the interactions can be thematically characterized as broadly about money, business, and commerce, they can also be said to draw on widely circulating discourses about social and linguistic difference. We found that the construction of difference varied qualitatively by the distance and intimacy of the relationships in play. We also found that a translanguaging repertoire was particularly evident in navigating sensitive cultural activities, attitudes and beliefs. This points to the usefulness of translanguaging to signpost an openness to, and interest in, social and linguistic diversity in the market place, where buying and selling are the order of the day