Current-induced two-level fluctuations in pseudo spin-valves (Co/Cu/Co) nanostructures

Two-level fluctuations of the magnetization state of pseudo spin-valve pillars Co(10 nm)/Cu(10 nm)/Co(30 nm) embedded in electrodeposited nanowires (~40 nm in diameter, 6000 nm in length) are triggered by spin-polarized currents of 10^7 A/cm^2 at room temperature. The statistical properties of the residence times in the parallel and antiparallel magnetization states reveal two effects with qualitatively different dependences on current intensity. The current appears to have the effect of a field determined as the bias field required to equalize these times. The bias field changes sign when the current polarity is reversed. At this field, the effect of a current density of 10^7 A/cm^2 is to lower the mean time for switching down to the microsecond range. This effect is independent of the sign of the current and is interpreted in terms of an effective temperature for the magnetization.Comment: 4 pages, 5 figures, revised version, to be published in Phys. Rev. Let

Electrochemical Surface Modification of Aluminium Sheets for Application to Nano-electronic Devices: Anodization Aluminium and Electrodeposition of Cobalt-Copper

A nano-porous anodized aluminium oxide layer was synthesized on the surface of bulk aluminium at a wide range of anodization voltages. The barrier layer at the pore bottom of anodized aluminium oxide layer was chemically etched to make good electrical contact for nanowires electrodeposited in the pores thus formed on metallic aluminium substrates. Cathodic polarization was examined at a wide range of cathode potentials to investigate the electrodeposition behaviour of Cu and Co into the pores. Co81Cu19/Cu multilayered nanowires were fabricated using a pulse-plating technique into the templates. Co-alloy layer and Cu layer thicknesses were adjusted to 10 nm, by controlling the deposition times. The temperature dependence of the resistance of Co81Cu19/Cu multilayered nanowires grown on the template presented clean metallic characteristics and a giant magnetoresistance (GMR) of 23% was reached at 4

Applications of active microwave imagery

The following topics were discussed in reference to active microwave applications: (1) Use of imaging radar to improve the data collection/analysis process; (2) Data collection tasks for radar that other systems will not perform; (3) Data reduction concepts; and (4) System and vehicle parameters: aircraft and spacecraft

Stratification of single-vessel coronary stenosis by ischemic threshold at the onset of wall motion abnormality during continuous monitoring of left ventricular function by semisupine exercise echocardiography.

peer reviewedWe studied the relation between the ischemic threshold at the onset of wall motion abnormality on exercise echocardiography (EE) and the severity of coronary stenosis in patients with 1-vessel coronary artery disease (CAD). We screened 216 consecutive patients who underwent coronary angiography and EE for suspected CAD. Ninety-five (74 men; age, 56 +/- 12 years) satisfied the study criteria, that is, the presence of 1-vessel disease or no evidence of CAD on angiography and a normal baseline echocardiogram. Eighty-seven patients had 1-vessel CAD on angiography, and exercise-induced wall motion abnormality occurred in 73 (77%). Optimal cutoff values of percent diameter stenosis and minimal lumen diameter for predicting a positive EE were 61% (sensitivity and specificity of 76%) and 1.12 mm (sensitivity and specificity of 74%). Among patients with positive EE, heart rate-blood pressure product at ischemic threshold was correlated with quantitative coronary stenosis (r = -0.72, P <.001). The ischemic threshold from continuous monitoring of left ventricular function during semisupine EE is correlated with the severity of coronary stenosis among patients with 1-vessel disease and a normal resting echocardiogram

The social aspects of rural life and farm tenantry, Cedar County, Iowa

This survey is a detailed study of 400 farms and farm families located in the northwest corner of Cedar county, Iowa. The area comprises Pioneer, Fremont, Red Oak, Linn, and the northeast part of Cass townships, exclusive of the incorporated towns of Stanwood and Mechanicsville. Only a record of the organizations and institutions in these towns is included in this study. The study is a detailed analysis of the population, economic, educational, religious and social conditions as found on the 400 farms and among the farm people on these farms. The area covers 128 square miles, or a little over one-fifth of the entire county

Rashba spin-orbit coupling and spin precession in carbon nanotubes

The Rashba spin-orbit coupling in carbon nanotubes and its effect on spin-dependent transport properties are analyzed theoretically. We focus on clean non-interacting nanotubes with tunable number of subbands $N$. The peculiar band structure is shown to allow in principle for Datta-Das oscillatory behavior in the tunneling magnetoresistance as a function of gate voltage, despite the presence of multiple bands. We discuss the conditions for observing Datta-Das oscillations in carbon nanotubes.Comment: 12 pages, published versio