Spin-reorientation transition ͑SRT͒ behaviors in ultrathin Co films grown on both Pt͑111͒ and Pd͑111͒ single-crystal substrates are investigated with in situ magneto-optical Kerr effects. At the region of SRT from the perpendicular to in-plane magnetization with the increasing of Co thickness, canted out-of-plane orientations are observed, from which we can determine not only the effective second-(K 2) but also fourth-(K 4) order anisotropy constants. Both the constants, which can be separated into bulk K 2b(4b) and interface anisotropy terms K 2s(4s) are essential to understand the stable canted out-of-plane magnetization. We found that the value of K 2s for Co/Pt͑111͒ is larger than that for Co/Pd ͑111͒, resulting in the later onset thickness and wider range of the observed SRT, while the negative small values of K 4s in the both systems yield the stable canted phases. In addition, we observed different polarization effects of Pd and Pt near the interfaces which might also contribute the contrasting SRT behaviors.

Background Mendelian randomization is a method for exploring observational associations to find evidence of causality. Objective To apply Mendelian randomization between risk factors/phenotypic traits (exposures) and PD in a large, unbiased manner, and to create a public resource for research. Methods We used two‐sample Mendelian randomization in which the summary statistics relating to single‐nucleotide polymorphisms from 5,839 genome‐wide association studies of exposures were used to assess causal relationships with PD. We selected the highest‐quality exposure genome‐wide association studies for this report (n = 401). For the disease outcome, summary statistics from the largest published PD genome‐wide association studies were used. For each exposure, the causal effect on PD was assessed using the inverse variance weighted method, followed by a range of sensitivity analyses. We used a false discovery rate of 5% from the inverse variance weighted analysis to prioritize exposures of interest. Results We observed evidence for causal associations between 12 exposures and risk of PD. Of these, nine were effects related to increasing adiposity and decreasing risk of PD. The remaining top three exposures that affected PD risk were tea drinking, time spent watching television, and forced vital capacity, but these may have been biased and were less convincing. Other exposures at nominal statistical significance included inverse effects of smoking and alcohol. Conclusions We present a new platform which offers Mendelian randomization analyses for a total of 5,839 genome‐wide association studies versus the largest PD genome‐wide association studies available (https://pdgenetics.shinyapps.io/MRportal/). Alongside, we report further evidence to support a causal role for adiposity on lowering the risk of PD. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

The easy axis of magnetization in Co x Pd 1Ϫx alloy films with xϭ0.35 is controllably engineered by varying the thickness, t Pd , of the Pd overlayers directly deposited on the alloy layers. In a Pd͑50 Å͒/CoPd ͑20 Å͒/Pd (t Pd ) sample with a 10-Å-height step-wedge Pd layer, the easy axis smoothly changes from in-plane orientation ͑t Pd ϭ0 Å͒ through canted out of plane ͑0Ͻt Pd Ͻ30 Å͒ to perpendicular ͑30рt Pd р60 Å͒. We also demonstrate that the spin switching is controllably reversible between in-plane and perpendicular orientations when the individual constituent layers of CoPd and Pd are alternately deposited. Smoothly continuous spin reorientation in a Pd ͑50 Å͒/CoPd ͑30 Å͒/Pd (t Pd ) film with increasing t Pd in a broad range of 0-150 Å convincingly evidences the magnetoelastic anisotropy origin for the observed spin switching.

We report in situ measurements of magnetoelastic coupling, B 2 , and stress, , in Co 35 Pd 65 alloy films epitaxially grown on a Cu/Si͑001͒ substrate in a thickness range of 1-10 ML by means of a highly sensitive optical deflection-detecting system. It was found that the value of B 2 increases from 0.72ϫ10 7 J/m 3 at 2 ML to 3.31ϫ10 7 J/m 3 at 10 ML. A second-order strain correction of B 2 ϭB b ϩC 1 ⑀ϩC 2 ⑀ 2 rather than a first-order one of B 2 ϭB b ϩC 1 ⑀ provides a better fit for the observed behavior of B 2 versus film strain, ⑀, where B b is the bulk value. The relationship between B 2 and ⑀ observed in the present study reveals that the second-order correction is crucial for understanding the dependence of B 2 on ⑀ in an ultrathin regime.