Latest developments of the spin-valve transistor

The magnetic hysteresis associated with the magnetization reversal of the free layer in a spin valve is analysed. A model is proposed which assumes a single-domain behavior of the free layer, and a fixed magnetization of the pinned layer. The model is then developed in the framework of the Stoner¿Wohlfarth coherent rotation model, where geometrical solutions are obtained by the astroid method. According to the strength of the interlayer exchange coupling, the applied field direction and the anisotropy arrangement of the magnetic layers, a general classification of the hysteresis loops is proposed. Quantitative comparisons with experiments on spin valves (e.g. NiFe/Cu/NiFe/FeMn) are shown

Metal bonding during sputter film deposition

We studied the bonding between two flat Si substrates with thin metal films. The bonding was accomplished during thin film sputter deposition on contamination free surfaces of metal films. In this work we used Ti and Pt. Successful bonding of these metal films (each having a thickness of 10–20 nm) occurred at room temperature over the entire bonded area (12 mm × 12 mm). Self-diffusion, particularly at grain boundaries and film surface, was the mechanism for bonding. Suitable metal bonding only occurred if the film surface roughness is sufficiently smaller than the self-diffusion length of metals. Particularly in the bonding of Ti to Ti films, transmission electron microscope observation revealed that complete crystalline grains had been formed across the former interface between the single thin Ti films. The interfaceless bonding can be explained by recrystallization of the Ti lattice due to the high self-diffusion coefficient of Ti. This technique would be applied to bonding of wafers to fabricate thin film devices or microsystems. Moreover, this bonding technology can be used with many different thin film materials and various semiconductor substrates

Cardiac resynchronization therapy in patients with a narrow QRS

Although cardiac resynchronization therapy (CRT) is indicated in patients with moderate to severe heart failure with a wide QRS complex (> 120 ms), current guidelines exclude many heart failure patients with a narrow QRS. Detecting mechanical dyssynchrony on echocardiography has become a promising tool in selecting patients with a narrow QRS who may respond to CRT. Several small single-center studies identified patients with a narrow QRS (using echocardiography-based dyssynchrony criteria) who responded favorably to CRT; however, the results of two recent pilot studies remain elusive. The results of the RethinQ study do not provide necessary evidence for making clinical treatment decisions in this population. The lack of definitive evidence is the strongest rationale for conducting an adequately powered, long-term, end point-driven, randomized controlled trial to investigate whether CRT therapy can improve morbidity and mortality outcomes in heart failure patients with a narrow QRS. Such a trial, the EchoCRT trial, has recently been launched