Andrew D. Kent

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The effect of domain walls on electron transport has been investigated in microfabricated Fe wires (0.65 to 20 mm linewidths) with controlled stripe domains. Magnetoresistance (MR) measurements as a function of domain wall density, temperature, and the angle of the applied field are used to determine the low field MR contributions due to conventional(More)
The magnetization of a magnetic material can be reversed by using electric currents that transport spin angular momentum. In the reciprocal process a changing magnetization orientation produces currents that transport spin angular momentum. Understanding how these processes occur reveals the intricate connection between magnetization and spin transport, and(More)
Current-induced magnetization dynamics in Co/Cu/Co trilayer nanopillars (approximately 100 nm in diameter) have been studied experimentally at low temperatures for large applied fields perpendicular to the layers. At 4.2 K an abrupt and hysteretic increase in resistance is observed at high current densities for one polarity of the current, comparable to the(More)
Current-induced excitations in Cu/Co/Cu single ferromagnetic layer nanopillars ( approximately 50 nm in diameter) have been studied experimentally as a function of Co layer thickness at low temperatures for large applied fields perpendicular to the layers. For asymmetric junctions current-induced excitations are observed at high current densities for only(More)
We report on room temperature ferromagnetic resonance (FMR) studies of [t Co|2t Ni]×N sputtered films, where 0.1 ≤ t ≤ 0.6 nm. Two series of films were investigated: films with same number of Co|Ni bilayer repeats (N=12), and samples in which the overall magnetic layer thickness is kept constant at 3.6 nm (N=1.2/t). The FMR measurements were conducted with(More)
—An annular magnetic memory that uses a spin-polarized current to switch the magnetization direction or helicity of a magnetic region is proposed. The device has magnetic materials in the shape of a ring (1 to 5 nm in thickness, 20 to 250 nm in mean radius and 8 to 100 nm in width), comprising a reference magnetic layer with a fixed magnetic helicity and a(More)
Activated CD8(+) T cells choose between terminal effector cell (TEC) or memory precursor cell (MPC) fates. We found that the signaling receptor Notch controls this 'choice'. Notch promoted the differentiation of immediately protective TECs and was correspondingly required for the clearance of acute infection with influenza virus. Notch activated a major(More)
It is believed the immune system can contribute to oncogenic transformation especially in settings of chronic inflammation, be activated during immunosurveillance to destroy early neoplastic cells before they undergo malignant outgrowth, and finally, can assist growth of established tumors by preventing clearance, remodeling surrounding tissue, and(More)
Large negative magnetoresistance ͑MR͒ observed in transport measurements of hcp Co films with stripe domains were recently reported and interpreted in terms of domain-wall ͑DW͒ scattering mechanism. Here detailed MR measurements, magnetic force microscopy, and micromagnetic calculations are combined to elucidate the origin of MR in this material. The large(More)