Reconfigurable superconducting vortex pinning potential for magnetic disks in hybrid structures

High resolution scanning Hall probe microscopy has been used to directly visualise the superconducting vortex behavior in hybrid structures consisting of a square array of micrometer-sized Py ferromagnetic disks covered by a superconducting Nb thin film. At remanence the disks exist in almost fully flux-closed magnetic vortex states, but the observed cloverleaf-like stray fields indicate the presence of weak in-plane anisotropy. Micromagnetic simulations suggest that the most likely origin is an unintentional shape anisotropy. We have studied the pinning of added free superconducting vortices as a function of the magnetisation state of the disks, and identified a range of different phenomena arising from competing energy contributions. We have also observed clear differences in the pinning landscape when the superconductor and the ferromagnet are electron ically coupled or insulated by a thin dielectric layer, with an indication of non-trivial vortex-vortex interactions. We demonstrate a complete reconfiguration of the vortex pinning potential when the magnetisation of the disks evolves from the vortex-like state to an onion-like one under an in-plane magnetic field. Our results are in good qualitative agreement with theoretical predictions and could form the basis of novel superconducting devices based on reconfigurable vortex pinning sites

Springer Proceedings in Physics

The aim of this study is to produce partially stabilized zirconia with MgO and to investigate effect of Al2O3 on partially stabilized zirconia. Zirconia nanopowders are synthesized by the precipitation method from zirconium sulfate precursors. Precipitates are dried at 80 degrees C for 72 h and 2.77 in weight percentage MgO powders were added to dried powders. Then this powders mixture is calcinated at 1300 degrees C for 1 h. Furthermore, wt%10 Al2O3 is added to calcinated powders and two different powders mixtures are produced. Each powder mixture are pressed and sintered at 1650 degrees C for 1 and 2 h in an electrical resistance furnace. MgO-ZrO2 samples have cubic, tetragonal and monoclinic zirconia phases while alumina added MgO-ZrO2-Al2O3 samples have dominantly monoclinic zirconia and spinel phases. In MgO-ZrO2-Al2O3 samples, MgO dissolves in Al2O3 and therefore MgO in zirconia matrix is not enough for the stabilization. Microhardness and fracture toughness of MgO-ZrO2 samples are higher than that of MgO-ZrO2-Al2O3 samples

AIP Conference Proceedings

In this study tin-multi walled carbon nanotube (Sn-MWCNT) lithium ion battery anodes were produced and their electrochemical galvanostatic charge/discharge tests were conducted at various (25 degrees C, 35 degrees C, 50 degrees C) temperatures to determine the cyclic behaviors of anode at different temperatures. Anodes were produced via vacuum filtration and DC magnetron sputtering technique. Tin was sputtered onto buckypapers to form composite structure of anodes. SEM analysis was conducted to determine morphology of buckypapers and Sn-MWCNT composite anodes. Structural and phase analyses were conducted via X-ray diffraction and Raman Spectroscopy technique. CR2016 coin cells were assembled for electrochemical tests. Cyclic voltammetry test were carried out to determine the reversibility of reactions between anodes and reference electrode between 0.01-2.0 V potential window. Galvanostatic charge/discharge tests were performed to determine cycle performance of anodes at different temperatures.https://doi.org/10.1063/1.494597

Springer Proceedings in Physics

This method can be used for the surface modification treatment of materials producing different surface properties. This paper presents the results obtained from an experimental work investigating the changes in some mechanical and microstructural surface properties of a 1.3343 steel (M2 high speed steel). In this work, a battery capacity of 800 0, and four different sample plasma gun nozzle distances were used. The consumable electrode is tungsten in this work. The samples were subjected to micro-hardness measurements and it was found that the hardness values of modified surfaces are five-seven times higher than that of untreated samples. The modified surface layers were examined using an optical microscope and X-ray analyses were carried out for all samples. It was observed that surface treatment had led to the formation of new phases in surface layers. SEM and EDS analyses were applied to modified surface

AIP Conference Proceedings

Basalt based glass-ceramics were prepared by conventional melt-quenching technique and subsequently converted to glass-ceramics by a controlled nucleation and crystallization process. Glass materials were obtained by melt at 1500 degrees C and quenched in cold water. The powder materials were made by milling and spin coating. The powders were applied on the 430 stainless steel interconnector material, and heat treatment was carried out. The interface characteristics between the glass-ceramic layer and interconnector were investigated by using X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The results showed that the basalt base glass-ceramic sealant material exhibited promising properties to use for SOFC

AIP Conference Proceedings

In the current study, the effect of particle size and velocity on solid particle erosive wear properties of glass-ceramics produced from cast basalt was investigated. The samples sectioned as the size of 50 x 50 x 12 mm were used for experimental studies. The samples were fixed 20 mm distance from the nozzle, and then they were eroded at 30 degrees,60 degrees,90 degrees impact angle by using alumina erosive media size of 106 - 150 mu and 63 - 106 mu m in different spray pressure 1.5, 3 and 4 bar for 20 sec. The particle size and velocity parameters were affected wear rates of basalt base glass-ceramics

Springer Proceedings in Physics

In this study, usage of gabbro and zeolite in the manufacturing of ceramic products were investigated. Three different compositions which consist of zeolite and gabbro as starting materials were prepared to manufacture a ceramic product. Dry mixing process was performed by ball milling for 10 h with alumina balls for all compositions. Compacted samples with 20 mm in diameter were obtained by dry pressing at the pressure of 400 MPa. Then, pressed samples were sintered at 900, 1000, 1100, 1150 and 1200 degrees C for 1 h in atmospheric conditions. Having completed the sintering process, the microstructural properties of products were examined by optic microscopy and SEM-EDS. The sintering behaviour of the samples produced at different firing temperatures was evaluated by the determination of the water absorption, bulk density and apparent porosity. Also, hardness of the samples was measured