The spin polarization of current injected into GaAs from a CoFe/MgO(100) tunnel injector is inferred from the electroluminescence polarization from GaAs/AlGaAs quantum well detectors. The polarization reaches 57% at 100 K and 47% at 290 K in a 5 T perpendicular magnetic field. Taking into account the field dependence of the luminescence polarization, the spin injection efficiency is at least 52...

We have made an experimental study of the tunneling density of states (DOS) in strong ferromagnetic thin films (CoFe) in proximity with a thick superconducting film (Nb) as a function of dF , the ferromagnetic thickness. Remarkably, we find that as dF increases, the superconducting DOS exhibits a scaling behavior in which the deviations from the normal-state conductance have a universal shape t...

objectives: micromechanical retention of resin cements to alloys is an important factor affecting the longevity of metal base restorations. this study aimed to compare the bond strength and etching pattern of a newly introduced experimental etchant gel namely nano met etch with those of conventional surface treatment techniques for nickel-chrome (ni-cr) and high noble alloys.  materials and met...

(HIPing), can improve the tribo-mechanical properties of cobalt-based alloys. The alloy selected for this investigation had a nominal wt.% composition of Co-30Cr-14W-1C, which is similar to the composition of the commercially available Stellite®4 alloy. The Hot Isostatic Pressed (HIPed) alloy had a much finer microstructure than the cast alloy, which showed a typical hypoeutectic dendritic micr...

Objectives: This study is undertaken to evaluate the dependence of bond strength of 100% fresh nonprecious alloy and the combination of 50% recast (used) alloy and 50% fresh alloy with three different veneering ceramic material. Materials and methods: To evaluate the shear bond strength between new and recast alloy nonprecious Ni-Cr alloy (System KN®, Adentatec, Germany) was used with three dif...

PURPOSE The aim of this study was to evaluate the effect of metal primers on the bonding of dental alloys and veneer resin. Polyvinylpyrrolidone solution's tarnish effect on bonding strength was also investigated. MATERIALS AND METHODS Disk-shape metal specimens (diameter 8 mm, thickness 1.5 mm) were made from 3 kinds of alloy (Co-Cr, Ti and Au-Ag-Pd alloy) and divided into 4 groups per each ...

A new kind of biomedical shape memory TiNiAg alloy with antibacterial function was successfully developed in the present study by the introduction of pure Ag precipitates into the TiNi matrix phase. The microstructure, mechanical property, corrosion resistance, ion release behavior in simulated body fluid, cytotoxicity and antibacterial properties were systematically investigated. The typical m...

Effects of B and Cr additions on magnetostriction and the mechanical properties of polycrystalline Fe83Ga17 alloy were investigated. Small addition of B increased magnetostriction of Fe83Ga17 alloy slightly, and improved the room temperature ductility and tensile strength significantly. The elongation and tensile strength of the (Fe83Ga17)99B1 alloy increased to 3.56% and 548MPa compared with t...

A nearby supernova (SN) explosion in the past can be confirmed by the detection of radioisotopes on Earth that were produced and ejected by the SN. We have now measured a well resolved time profile of the 60Fe concentration in a deep-sea ferromanganese crust and found a highly significant increase 2.8 Myr ago. The amount of 60Fe is compatible with the deposition of ejecta from a SN at a distanc...

Dynamic recrystallization (DRX) is almost universally observed in the microstructure of adiabatic shear bands. It is usually admitted that DRX results from the large temperatures that develop in the band along with very high local strains. This paper reports the observation of dynamically recrystallized nanograins in Ti6Al4V alloy specimens that were impact loaded to only half the failure strai...