Spin Drift in Highly Doped n-type Si

A quantitative estimation of spin drift velocity in highly doped n-type silicon (Si) at 8 K is presented in this letter. A local two-terminal Hanle measurement enables the detection of a modulation of spin signals from the Si as a function of an external electric field, and this modulation is analyzed by using a spin drift-diffusion equation and an analytical solution of the Hanle-type spin precession. The analyses reveal that the spin drift velocity is linearly proportional to the electric field. The contribution of the spin drift effect to the spin signals is crosschecked by introducing a modified nonlocal four-terminal method.Comment: 16 pages, 3 figure

Room-Temperature Electron Spin Transport in a Highly Doped Si Channel

We report on the first demonstration of generating a spin current and spin transport in a highly doped Si channel at room temperature (RT) using a four-terminal lateral device with a spin injector and a detector consisting of an Fe/MgO tunnel barrier. Spin current was generated using a nonlocal technique, and spin injection signals and Hanle-type spin precession were successfully detected at 300 K, thus proving spin injection with the elimination of spurious signals. The spin diffusion length and its lifetime at RT were estimated to be 0.6 \"im and 1.3 ns by the Hanle-type spin precession, respectively.Comment: 14 pages, 4 Figure

The effect of spin drift on spin accumulation voltages in highly-doped Si

An investigation was carried out into the effect of spin drift on spin accumulation signals in highly-doped Si using non-local 4-terminal (NL-4T) and 3-terminal (NL-3T) methods. The spin signals in the NL-4T scheme were not affected by spin drift, and the bias dependence was governed by whether spins were injected into or extracted from the Si channel. In contrast, the spin signal was strongly modulated by the bias electric field in the NL-3T scheme. The bias electric field dependence of the spin signals in the NL-3T method was quantitatively clarified using the spin drift-diffusion equation, and the results can be reasonably explained.Comment: 14 pages, 3 figure

Long-term observation of fibrillation cycle length in patients under angiotensin II receptor blocker therapy for chronic atrial fibrillation

AbstractIntroductionThe long-term effect of angiotensin II receptor blockers (ARBs) on atrial fibrillation (AF) is unclear. In this study, we evaluated the change in the fibrillation cycle length (FCL) in patients under long-term ARB therapy for chronic AF.Methods and resultsThe study population consisted of 25 chronic AF patients who were prescribed the same medication for more than 6 years and in whom specific ECG recording for FCL evaluation could be performed before and after the 6-year observation period. The patients were divided into 2 groups: those with and without ARB (ARB group and non-ARB group and n=15 and 10, respectively). FCL was calculated by the spectral analysis of the fibrillation waves in the surface ECG. There was no significant difference in the clinical characteristics between the 2 groups. In the ARB group, the mean FCL was prolonged from 154±20ms to 187±37ms (p=0.005), whereas it remained unchanged in the non-ARB group (150±12ms vs. 149±10ms). In the comparison between patients with and those without FCL prolongation (>30ms; n=6 and 19, respectively), a significant difference was observed only in those prescribed ARBs.ConclusionIn cases of chronic AF, FCL might be prolonged under long-term ARB treatment

An investigation of the inverted Hanle effect in highly-doped Si

The underlying physics of the inverted Hanle effect appearing in Si was experimentally investigated using a Si spin valve, where spin transport was realized up to room temperature. No inverted-Hanle-related signal was observed in a non-local 4-terminal scheme even the same ferromagnetic electrode was used, whereas the signal was detected in a non-local 3-terminal scheme. Although the origin of the inverted Hanle effect has been thought to be ascribed to interfacial roughness beneath a ferromagnetic electrode, our finding is inconsistent with the conventional interpretation. More importantly, we report that there were two different Hanle signals in a non-local 3-terminal scheme, one of which corresponds to the inverted Hanle signal but the other is ascribed to spin transport. These results strongly suggest that (1) there is room for discussion concerning the origin of the inverted Hanle effect, and (2) achievement of spin transport in a non-local 4-terminal scheme is indispensable for further understanding of spin injection, spin transport and spin coherence in Si. Our new findings provide a new and strong platform for arising discussion of the physical essence of Hanle-related spin phenomena.Comment: 16 pages, 3 figures (To appear in Physical Review B (Rapid Communications)

Evidence for Association of the rs17822931-A Allele in ABCC11 with a Decreased Risk of Estrogen Receptor-negative Breast Cancer

The rs17822931 SNP of the human ABCC11 gene determines earwax types, and is also associated with some functions of apocrine glands, including the mammary gland. Nevertheless, whether the ABCC11 polymorphism is correlated with estrogen receptor (ER) status of breast cancer (BC) remains unclear. To investigate the correlation between rs17822931 and BC, we screened the genotypes in a total of 276 and 295 histological BC samples collected from Japanese and Ukrainian BC patients, and 269 and 264 ethnically-matched healthy individuals, respectively, using TaqManTM PCR. Genotype frequencies at rs178229131 in Japanese and Ukrainian BC patients were not significantly different from those in their respective control populations. Consistently, no correlation between rs178229131 and the susceptibility to BC was found. The AA genotype, which corresponds to dry earwax, occurred less frequently in ER -negative BC in Japanese [odds ratio, 0.48; 95% confidential interval, 0.29-0.80] but not in Ukrainian patients although a similar correlation was weakly observed. Our results indicate that the rs178229131-A allele may be important in reducing the risk of ER -negative BC development

Electrical Spin Injection into Silicon using MgO Tunnel Barrier

We observed spin injection into silicon through Fe/MgO tunnel barrier by using non-local magnetoresistance measurement technique. Fe/MgO tunnel barrier contacts with a lateral spin valve structure were fabricated on phosphorous doped silicon-on-insulator substrate. Spin injection signals in the non-local scheme were observed up to 120K, which is the highest value where band transferred spins in Si have ever been reported, and spin diffusion length was estimated to be about 2.25um at 8K. Temperature dependence and injection current dependence of the non-local voltage were also investigated. It is clarified that MgO tunnel barrier is effective for the spin injection into silicon.Comment: 15pages, 4 figures. To appear in Applied Physics Expres