Articles you may be interested inA simple model to predict the temperature dependence of elastic moduli of bulk metallic glassesThe dynamic Young's moduli and the internal friction of fused quartz, Pyrex glass, and soft glass rods were measured at a frequency of 37 kilocycles, in longitudinal vibration, within the temperature range -170° to 1000°C. The moduli of Pyrex and quartz increased with rising temperature, up to the softening point of the glass, while that of soft glass decreased. All three moduli were approximately linear with respect to the temperature over most of the measurement interval. Internal friction maxima were noted at high temperatures, while at the lowest measurement temperatures a significant increase in background damping occurred. A brief recapitulation of existing theory is given and employed to interpret the internal friction data. It is suggested that, in microscopically inhomogeneous media, the diffusion measurement by internal friction methods is not equivalent to the determination by other teclmiques.
Thin C:N films were prepared by rf diode sputtering of a graphite target in a mixed argon/nitrogen plasma. We have observed a systematic variation of the properties of these C:N films with an increase in the nitrogen partial pressure. XPS, AES, and TEM studies show that nitrogen will stabilize the diamond sp3 bonding. From XPS studies, we found that the density of our C:N films is increased from 1.37 × 1023 atoms/cm3 to 1.63 × 1023 atoms/cm3 using a 100% nitrogen plasma. The energy gap of our nitrogen carbon also shows an increase from 1.1 eV to 1.4 eV using a 100% nitrogen plasma. The mechanical properties also are shown to be enhanced for certain applications. By using the same method, we can also show that it can produce 100% amorphous C:N films which are more diamond-like as compared with other methods.
In this study, the magnetic behavior of NiFe/NiO bilayers has been investigated. The relationship between the magnetic properties and interfacial interaction has been briefly discussed. Since magnetic properties of the bilayers are mainly determined by interfacial magnetic interaction, in this article, not only unidirectional interfacial anisotropy has been used to explain exchange field, Hex; also, for the first time, uniaxial interfacial anisotropy is introduced to describe interfacial interaction affecting the magnetic properties, especially coercivity Hc of the bilayers. In addition, a model is proposed to explain the magnetic behavior of the bilayers. The model has been tested by experiment. The experimental results are consistent with the model prediction, and this also confirms the assumption that the magnetization of the bilayer reverses by magnetic rotation.
We report values of the giant magnetoresistance (GMR) effect exceeding 21% in symmetric spin valves, the highest values ever reported for such structures. The key elements in this achievement are the use of a Co/Cu/Co/Cu/Co multilayer in which the center Co layer is substantially thicker than the outer Co layers and the use of the antiferromagnetic insulator NiO at the top and bottom to pin the adjacent Co layers magnetically. The relative Co layer thicknesses suggest that some specular scattering of conduction electrons may occur at the metal/insulator interfaces and may enhance the GMR.
We have attempted to optimize the values of the giant magnetoresistance in symmetric spin valves of the type NiO/Co/Cu/Co/Cu/Co/NiO (achieving 23.4%) and in bottom spin valves of the type Co/Cu/Co/NiO (achieving 17.0%), the largest values ever reported for such structures. The key elements in this achievement are improved vacuum conditions and careful attention to the film thicknesses.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.