ABSTRACT
We present the measurement of ferromagnetic resonance (FMR-)driven spin pumping and three-terminal electrical spin injection within the same silicon-based device. Both effects manifest in a dc spin accumulation voltage V_{s} that is suppressed as an applied field is rotated to the out-of-plane direction, i.e., the oblique Hanle geometry. Comparison of V_{s} between these two spin injection mechanisms reveals an anomalously strong suppression of FMR-driven spin pumping with increasing out-of-plane field H_{app}^{z}. We propose that the presence of the large ac component to the spin current generated by the spin pumping approach, expected to exceed the dc value by 2 orders of magnitude, is the origin of this discrepancy through its influence on the spin dynamics at the oxide-silicon interface. This convolution, wherein the dynamics of both the injector and the interface play a significant role in the spin accumulation, represents a new regime for spin injection that is not well described by existing models of either FMR-driven spin pumping or electrical spin injection.
ABSTRACT
We have investigated spin pumping from Y3Fe5O12 thin films into Cu, Ag, Ta, W, Pt, and Au with varying spin-orbit coupling strengths. From measurements of Gilbert damping enhancement and inverse spin Hall signals spanning 3 orders of magnitude, we determine the spin Hall angles and interfacial spin mixing conductances for the six metals. The spin Hall angles largely vary as Z(4) (Z: atomic number), corroborating the role of spin-orbit coupling. Amongst the four 5d metals, the variation of the spin Hall angle is dominated by the sensitivity of the d-orbital moment to the d-electron count, confirming theoretical predictions.
ABSTRACT
An iron filled carbon nanotube (FeCNT), a 10-40 nm ferromagnetic nanowire enclosed in a protective carbon tube, is an attractive candidate for a magnetic force microscopy (MFM) probe as it provides a mechanically and chemically robust, nanoscale probe. We demonstrate the probe's capabilities with images of the magnetic field gradients close to the surface of a Py dot in both the multi-domain and vortex states. We show the FeCNT probe is accurately described by a single magnetic monopole located at its tip. Its effective magnetic charge is determined by the diameter of the iron wire and its saturation magnetization 4πM(s) ≈ 2.2 × 10(4)G. A magnetic monopole probe is advantageous as it enables quantitative measurements of the magnetic field gradient close to the sample surface. The lateral resolution is defined by the diameter of the iron wire and the probe-sample separation.
ABSTRACT
In order to know the left colon anastomosis evolution with perforation and focus peritonitis, 40 male rats, Wistar-TECPAR, 135 days old and weighing 345 g in average were divided in two groups of 20 animals each. Group A was the control group and group B the experimental group. Submitted to a laparotomy, the B rats had a left colon wound 0.3 cm in diameter, 1.5 cm in distance from the peritoneal reflection. The A rats had only a intestinal handling. All rats had a new laparotomy after 24 hours; a resection and end-to-end anastomosis. An analysis was made on third and seventh days of the macro and microscopic evolution and bursting pressure. On the second laparotomy, in the B rats, peritonitis was absent and only local reaction was present. Dehiscence, fistula or peritonitis were absent at the observation on the third and seventh days. The anastomosis evolution was similar in the two groups. It was concluded that the focus peritonitis was not sufficient to modify the healing process of the left colon anastomosis in rats during the period studied.
