Methods to induce perpendicular magnetic anisotropy in full-Heusler Co2FeSi thin layers in a magnetic tunnel junction structure

In this study, to obtain perpendicular magnetic tunnel junctions (p-MTJs) using half-metallic ferromagnets (HMFs), several methods were developed to induce perpendicular magnetic anisotropy (PMA) in full-Heusler Co2FeSi (CFS) alloy thin layers in an MTJ multilayer composed of a layered CFS/MgO/CFS structure. Oxygen exposure at 2.0 Pa for 10 min after deposition of the bottom CFS layer was effective for obtaining PMA in the CFS layer. One of the reasons for the PMA is the formation of nearly ideal CFS/MgO interfaces due to oxygen exposure before the deposition of the MgO layer. The annealing process was effective for obtaining PMA in the top CFS layer capped with a Pd layer. PMA was clearly observed in the top CFS layer of a Cr(40 nm)/Pd(50 nm)/bottom CFS(0.6 nm)/MgO(2.0 nm)/top CFS(0.6 nm)/Pd(10 nm) multilayer, where the top CFS and Pd thin films were deposited at RT and subsequently annealed at 300{\deg}C. In addition to the continuous layer growth of the films, the crystalline orientation alignment at the top CFS/Pd interface probably attributes to the origin of PMA at the top CFS layer.Comment: 16 pages, 4 figure

The unusual case of plastic deformation and high dislocation densities with the cold sintering of the piezoelectric ceramic K0.5Na0.5NbO3

K0.5Na0.5NbO3 (KNN) can be readily densified using the cold sintering process, but despite observing high relative permittivity, the ferroelectric hysteresis is strongly suppressed along with a major suppression in the all-important piezoelectric properties. In this study, KNN is fabricated using a NaOH+KOH transient flux under a uniaxial pressure of 400 MPa and heating to 300 °C for 2 h to drive densification to 93% theoretical. It is only after a secondary heat treatment that we observe improvements of the ferroelectric hysteresis and piezoelectric properties. From a detailed structural-property-processing study using analytical transmission electron microscopy (TEM), X-ray line broadening and high field dielectric characterization methodologies we conclude that there is an unusual in-situ plastic deformation process that takes place in addition to the densification under the cold sintering process. High densities of dislocations within grains were observed that lead to multiple pinning sites that impact both the intrinsic and extrinsic contributions to the high field dielectric and piezoelectric properties. Annealing significantly reduced the dislocation density in the highly defective crystallites, observed directly from the TEM and from the sharpening of the X-ray diffraction peaks, resulting in piezoelectric and ferroelectric properties that approached those of conventionally sintered KNN

The unusual case of plastic deformation and high dislocation densities with the cold sintering of the piezoelectric ceramic K0.5Na0.5NbO3

K0.5Na0.5NbO3 (KNN) can be readily densified using the cold sintering process, but despite observing high relative permittivity, the ferroelectric hysteresis is strongly suppressed along with a major suppression in the all-important piezoelectric properties. In this study, KNN is fabricated using a NaOH+KOH transient flux under a uniaxial pressure of 400 MPa and heating to 300 °C for 2 h to drive densification to 93% theoretical. It is only after a secondary heat treatment that we observe improvements of the ferroelectric hysteresis and piezoelectric properties. From a detailed structural-property-processing study using analytical transmission electron microscopy (TEM), X-ray line broadening and high field dielectric characterization methodologies we conclude that there is an unusual in-situ plastic deformation process that takes place in addition to the densification under the cold sintering process. High densities of dislocations within grains were observed that lead to multiple pinning sites that impact both the intrinsic and extrinsic contributions to the high field dielectric and piezoelectric properties. Annealing significantly reduced the dislocation density in the highly defective crystallites, observed directly from the TEM and from the sharpening of the X-ray diffraction peaks, resulting in piezoelectric and ferroelectric properties that approached those of conventionally sintered KNN

Towards a Rational Design of Zeolite-Polymer Composite Nanofibers for Efficient Adsorption of Creatinine

This report describes the compositional and structural design strategy of a zeolite-polymer composite nanofiber mesh for the efficient removal of uremic toxins towards blood purification application. The nanofiber is fabricated by electrospinning composite solution of biocompatible poly(ethylene-co-vinyl alcohol) (EVOH) and zeolite particles which are capable of selectively adsorbing uremic toxins such as creatinine. By controlling electrospinning conditions carefully, the incorporated zeolites in EVOH were found to correspond closely to the feed ratios. Elemental mapping images of Si show that zeolites were uniformly blended within the fibers. The fabricated composite fibers successfully adsorbed creatinine from solution and the adsorption capacity reached a maximum at 12 h. The crystallinity of the nanofiber was also controlled by varying the composition of ethylene content in EVOH. Less crystallinity resulted in higher creatinine adsorption capacity due to the barrier property of EVOH. Cytotoxicity assay demonstrated that the composite fibers showed less toxicity than free zeolite particles which killed more than 95% of cells. The proposed composite fibers, therefore, have the potential to be utilized as a new approach to removing creatinine selectively from the bloodstream

退院時の6 分間歩行距離は退院3 か月後の身体活動量に影響する : 軽症脳梗塞患者における前向きコホート研究

研究論文Original Articles　【目的】本研究の目的は，急性期病院退院後の軽症脳梗塞患者の身体活動量に影響する退院時の要因を明らかにすることであった．【方法】研究デザインは，前向きコホート研究である．軽症脳梗塞患者を対象に身体活動量に関連する要因を退院時に測定し，退院2 週後と3 か月後の身体活動量をオムロン活動量計Active style Pro HJA-750C を用いて測定し，退院後の身体活動量に影響する退院時の要因を検討した．【結果】重回帰分析の結果，退院3 か月後の身体活動量に影響する要因として6 分間歩行距離（β＝ 0.675，p ＜ 0.001）のみが抽出された（自由度調整済みR2 ＝ 0.432，p ＜ 0.001）．【結論】急性期病院退院後の軽症脳梗塞患者の身体活動量には，退院時の6 分間歩行距離が影響することが明らかになった．退院3 か月後の身体活動量の向上には，退院時の6 分間歩行距離を高めることが重要であることが示唆された．【Object】The purpose of this study was to clarify the factors at the time of discharge that affect the physical activity level in patients with minor ischemic stroke after discharge from the acute care hospital.【Methods】This is a prospective cohort study.　We measured factors related to physical activity level at the time of discharge for patients with minor ischemic stroke, and used OMRON\u27s Active Style Pro HJA-750C to measure physical activity level 2 weeks and 3 months after discharge.　We used multiple regression analysis to examine factors at discharge that affect physical activity level after discharge.【Result】As a result of multiple regression analysis, only 6-minute walking distance ( β = 0.675, p <0.001) was extracted as a factor affecting physical activity level 3 months after discharge.【Conclusion】It was clarified that the 6-minute walking distance at the time of discharge affected the physical activity level of patients with minor ischemic stroke after discharge from the acute hospital. These results suggest that it is important to increase the walking distance for 6 minutes at the time of discharge in order to improve physical activity level 3 months after discharge