RESUMEN
The successful operation of spin-based data storage devices depends on thermally stable magnetic bits. At the same time, the data-processing speeds required by today's technology necessitate ultrafast switching in storage devices. Achieving both thermal stability and fast switching requires controlling the effective damping in magnetic nanoparticles. By carrying out a surface chemical analysis, we show that through exposure to ambient oxygen during processing, a nanomagnet can develop an antiferromagnetic sidewall oxide layer that has detrimental effects, which include a reduction in the thermal stability at room temperature and anomalously high magnetic damping at low temperatures. The in situ deposition of a thin Al metal layer, oxidized to completion in air, greatly reduces or eliminates these problems. This implies that the effective damping and the thermal stability of a nanomagnet can be tuned, leading to a variety of potential applications in spintronic devices such as spin-torque oscillators and patterned media.
RESUMEN
The authors measured thyroid-stimulating hormone (TSH) response to thyrotropin-releasing hormone in 32 healthy volunteers who had never sought or received psychiatric treatment. Nine (28%) had a family or personal history of depression or alcoholism. Five of these nine subjects and one of 22 subjects without such a history showed TSH blunting (TSH data were not available for one subject). This difference was statistically highly significant. Although there were sex differences in TSH response, TSH blunting occurred most frequently in men with a family or personal history of depression or alcoholism. The fault may have utility as a marker of past episodes or as a true marker of trait.