Stability of switchable SmS for piezoresistive applications

In this work samarium sulfide thin films have been deposited by using e-beam evaporation under H2S atmosphere. Optical and structural properties were studied in several environments. The stability in several environments allows further processing into piezoelectronic devices

Samarium monosulfide (SmS) : reviewing properties and applications

In this review, we give an overview of the properties and applications of samarium monosulfide, SmS, which has gained considerable interest as a switchable material. It shows a pressure-induced phase transition from the semiconducting to the metallic state by polishing, and it switches back to the semiconducting state by heating. The material also shows a magnetic transition, from the paramagnetic state to an antiferromagnetically ordered state. The switching behavior between the semiconducting and metallic states could be exploited in several applications, such as high density optical storage and memory materials, thermovoltaic devices, infrared sensors and more. We discuss the electronic, optical and magnetic properties of SmS, its switching behavior, as well as the thin film deposition techniques which have been used, such as e-beam evaporation and sputtering. Moreover, applications and possible ideas for future work on this material are presented. Our scope is to present the properties of SmS, which were mainly measured in bulk crystals, while at the same time we describe the possible deposition methods that will push the study of SmS to nanoscale dimensions, opening an intriguing range of applications for low-dimensional, pressure-induced semiconductor-metal transition compounds

Switchable Piezoresistive SmS thin films on large area

Samarium monosulfide (SmS) is a switchable material, showing a pressure-induced semiconductor to metal transition. As such, it can be used in different applications such as piezoresistive sensors and memory devices. In this work, we present how e-beam sublimation of samarium metal in a reactive atmosphere can be used for the deposition of semiconducting SmS thin films on 150 mm diameter silicon wafers. The deposition parameters influencing the composition and properties of the thin films are evaluated, such as the deposition rate of Sm metal, the substrate temperature and the H2S partial pressure. We then present the changes in the optical, structural and electrical properties of this compound after the pressure-induced switching to the metallic state. The back-switching and stability of SmS thin films are studied as a function of temperature and atmosphere via in-situ X-ray diffraction. The thermally induced back switching initiates at 250 degrees C, while above 500 degrees C, Sm2O2S is formed. Lastly, we explore the possibility to determine the valence state of the samarium ions by means of X-ray photoelectron spectroscopy

SmS/EuS/SmS tri-layer thin films : the role of diffusion in the pressure triggered semiconductor-metal transition

While SmS thin films show an irreversible semiconductor-metal transition upon application of pressure, the switching characteristics can be modified by alloying with other elements, such as europium. This manuscript reports on the resistance response of tri-layer SmS/EuS/SmS thin films upon applying pressure and on the correlation between the resistance response and the interdiffusion between the layers. SmS thin films were deposited by e-beam sublimation of Sm in an H2S atmosphere, while EuS was directly sublimated by e-beam from EuS. Structural properties of the separate thin films were first studied before the deposition of the final nanocomposite tri-layer system. Piezoresistance measurements demonstrated two sharp resistance drops. The first drop, at lower pressure, corresponds to the switching characteristic of SmS. The second drop, at higher pressure, is attributed to EuS, partially mixed with SmS. This behavior provides either a well-defined three or two states system, depending on the degree of mixing. Depth profiling using x-ray photoelectron spectroscopy (XPS) revealed partial diffusion between the compounds upon deposition at a substrate temperature of 400 degrees C. Thinner tri-layer systems were also deposited to provide more interdiffusion. A higher EuS concentration led to a continuous transition as a function of pressure. This study shows that EuS-modified SmS thin films are possible systems for piezo-electronic devices, such as memory devices, RF (radio frequency) switches and piezoresistive sensors

Comics as Research, Comics for Impact: The Case of Higher Fees, Higher Debts

Researchers have turned to comics as outputs incorporating their research findings. These comics are print and/or online publications that can lead to the wider adoption of research and enhance educational practices, widen public engagement, and improve the possibilities for research to influence public policy. This article presents an interview with Professor Katy Vigurs about Higher Fees, Higher Debts: Greater Expectations of Graduate Futures?, a comic based on a research report produced for the Society for Research into Higher Education (2016). In order to contextualize the interview, this article also provides an introduction to non-fiction comics research, and concludes with reflections on comics as a way of doing research. This article seeks to document and encourage further knowledge-exchange between the higher education sector and comics practitioners, and between researchers using comics in their research or as a means to disseminate their own research and those scholars who research comics as their main object of study

Measurement of Young’s modulus of thin SmS films by Nanoindentation and surface acoustic wave

Nanoindentation was used to measure the elastic modulus of thin semiconducting form of Samarium Sulphide (SmS) thin films with nominal thickness of 100 nm, 200 nm and 400 nm on silicon substrate at different loads. The indentation results are fitted with modified King’s model [1] to exclude the effect of substrate, of which the Young’s moduli of films are consistent with measurement from Laser Surface Acoustic Wave system (LaWave) and calculated results from literature [2]. [1] [1] R. Saha, W. D. Nix, Acta Mater. 50 (2002) 23. [2] E. G. Soboleva et al, Appl. Mech. Mater. 770 (2015) 137; V. V. Kaminskiy et al, Sol. Sys. Res., 48 (2014) 561

Remix as Professional Learning: Educators’ Iterative Literacy Practice in CLMOOC

The Connected Learning Massive Open Online Collaboration (CLMOOC) is an online professional development experience designed as an openly networked, production-centered, participatory learning collaboration for educators. Addressing the paucity of research that investigates learning processes in MOOC experiences, this paper examines the situated literacy practices that emerged as educators in CLMOOC composed, collaborated, and distributed multimediated artifacts. Using a collaborative, interactive visual mapping tool as participant-researchers, we analyzed relationships between publically available artifacts and posts generated in one week through a transliteracies framework. Culled data included posts on Twitter (n = 678), a Google+ Community (n = 105), a Facebook Group (n = 19), a blog feed (n = 5), and a “make� repository (n = 21). Remix was found to be a primary form of interaction and mediator of learning. Participants not only iterated on each others’ artifacts, but on social processes and shared practices as well. Our analysis illuminated four distinct remix mobilities and relational tendencies—bursting, drifting, leveraging, and turning. Bursting and drifting characterize the paces and proximities of remixing while leveraging and turning are activities more obviously disruptive of social processes and power hierarchies. These mobilities and tendencies revealed remix as an emergent, iterative, collaborative, critical practice with transformative possibilities for openly networked web-mediated professional learning.ECU Open Access Publishing Support Fun

Licking planets and stomping on buildings: children’s interactions with curated spaces in virtual reality

This visual essay draws upon data from a commercially funded project on which I was the lead researcher (Yamada-Rice et al. 2017). The study was undertaken to develop a set of best practices for the production of Virtual Reality (VR) content for children. The project combined large-scale quantitative data from a global survey with qualitative methods used to observe and interview a smaller sample of 8–12 year-olds. There was also a health and safety element that tested for changes in vision and balance pre and post VR use. This article draws from the qualitative dataset that investigated children’s interaction with a range of VR content and devices, the aspects that engaged them and how easy it was to use