Observation and theoretical calculations of voltage-induced large magnetocapacitance beyond 330% in MgO-based magnetic tunnel junctions

Magnetic tunnel junctions (MTJs) in the field of spintronics have received enormous attention owing to their fascinating spin phenomena for fundamental physics and potential applications. MTJs exhibit a large tunnel magnetoresistance (TMR) at room temperature. However, TMR depends strongly on the bias voltage, which reduces the magnitude of TMR. On the other hand, tunnel magnetocapacitance (TMC), which has also been observed in MTJs, can be increased when subjecting to a biasing voltage, thus exhibiting one of the most interesting spin phenomena. Here we report a large voltage-induced TMC beyond 330% in MgO-based MTJs, which is the largest value ever reported for MTJs. The voltage dependence and frequency characteristics of TMC can be explained by the newly proposed Debye-Fröhlich model using Zhang-sigmoid theory, parabolic barrier approximation, and spin-dependent drift diffusion model. Moreover, we predict that the voltage-induced TMC ratio could reach over 3000% in MTJs. It is a reality now that MTJs can be used as capacitors that are small in size, broadly ranged in frequencies and controllable by a voltage. Our theoretical and experimental findings provide a deeper understanding on the exact mechanism of voltage-induced AC spin transports in spintronic devices. Our research may open new avenues to the development of spintronics applications, such as highly sensitive magnetic sensors, high performance non-volatile memories, multi-functional spin logic devices, voltage controlled electronic components, and energy storage devices.

A prenatal diagnosis of unusual aortopulmonary communication: tubular aortopulmonary window

We described a very rare case of aorto-pulmonary communication with right aortic arch and crossed pulmonary artery that cannot be placed in the typical anatomic classification of aortopulmonary window. At 23 weeks gestation, fetal echocardiography revealed a large tunnel-like communication connecting the great vessels proximal to the main pulmonary artery bifurcation, rather than a classic aortopulmonary window between the ascending aorta and the main pulmonary artery.

An assessment on the inner lining need for a large-span tunnel (a case from Turkey, Akyazı Tunnel, Trabzon)

Stability of large underground structures depends on not only rock mass conditions but also excavation stages and support systems. In addition, complexity of geological conditions and interaction of excavation with in situ conditions affect the performance of design. The Akyazı tunnel (Trabzon, Turkey) is 2478 m long and was designed as 3 lanes and double tubes, and the number of lanes at the junction part increases to 5. Tunnel cross-sectional area from the Akyazı tunnel reaches 3 lanes and 150 m2 to 5 lanes and 438 m2 gradually. The width of the tunnel at the junction point reaches to 31 m. In this study, the necessity of inner lining concrete in tunnels excavated in good rock mass conditions is assessed and the results of the analyses are discussed. The inner lining concrete increases the cost of tunnel construction, as well as extending the construction period. With the procedure followed in the Akyazı tunnel, the top heading part of the tunnel was constructed without inner lining. No stability and drainage problem have not been encountered for 4 years. Currently, the tunnel construction was completed successfully, and the tunnel was opened to traffic. Consequently, the excavation stages, support systems described, and especially inner lining necessities discussed in this study may be applicable for extremely large tunnel sections.

The cryo-EM structure of an ERAD protein channel formed by tetrameric human Derlin-1

Endoplasmic reticulum–associated degradation (ERAD) is a process directing misfolded proteins from the ER lumen and membrane to the degradation machinery in the cytosol. A key step in ERAD is the translocation of ER proteins to the cytosol. Derlins are essential for protein translocation in ERAD, but the mechanism remains unclear. Here, we solved the structure of human Derlin-1 by cryo–electron microscopy. The structure shows that Derlin-1 forms a homotetramer that encircles a large tunnel traversing the ER membrane. The tunnel has a diameter of about 12 to 15 angstroms, large enough to allow an α helix to pass through. The structure also shows a lateral gate within the membrane, providing access of transmembrane proteins to the tunnel, and thus, human Derlin-1 forms a protein channel for translocation of misfolded proteins. Our structure is different from the monomeric yeast Derlin structure previously reported, which forms a semichannel with another protein.

Substantial and stable magnetoresistance and spin conductance in phosphorene-based spintronic devices with Co electrodes

Phosphorene-based device with fcc Co(111) electrodes shows excellent spin transport characteristics: large tunnel magnetoresistance ratio and stable spin injection efficiency.

Tl0.6Mo3S5, an original large tunnel-like molybdenum sulfide with Mo zigzag chains and disordered Tl cations

A novel family of tunnel-like molybdenum sulfide is presented. Strongly disordered Tl cations residing in the large tunnels influence significantly the thermal transport.