Magnetic structure of domain walls confined in a nano-oxide layer

In the recent years, a spin-valve was developed with a current-confined-path structure consisting of a non-oxide-layer (NOL). We analyze magnetic structures of the current-confinedpath in the nano-oxide layer sandwiched between ferromagnetic electrodes and clarify the dependency of the magnetic structure on the shape and size of the current-confined-path. Our results of stiffness energy density and thermal stability shows that we should fabricate a CPP spin-valve with narrow current-confinedpaths with large aspect ratio and strong constriction in order to enhance the MR ratio.Comment: 3 pages, 3 figures, proceedings paper of Intermag 200

原発性副甲状腺機能亢進症, 尿管ポリープおよび腎盂結石を伴ったKlinefelter症候群の1例

副甲状腺機能亢進症, 右尿管ポリープ, および右腎盂結石を合併したKlinefelter症候群の1例を経験し, その臨床経過を報告するとともに文献的考察を加えた。〔症例〕 55歳男性で右側腹部痛を主訴として来院した。理学的所見で外陰部は男性型であるが発育不良で両側睾丸は小さくeunuchoidal habitusを呈した。既往歴に右尿管結石で5回自然排石が認められたほかに, 16年前gynecomastiaのためmastectomyを受けた事がある。身長171 cm, arm span 177.8 cmで体毛は少なく染色体検査は47XXYでKlinefelter症候群と診断した。血清LH, FSHは高値でテストステロン値は低値を示した。排泄性腎盂造影で右水腎症と右腎孟結石が認められ, 逆行性腎盂造影により右尿管上部に水腎症の原因となる腫瘍による多発性陰影欠損がみられ, 尿細胞診も悪性腫瘍を疑わせたため, 右腎尿管全摘術を施行した。尿管腫瘍は組織学的には多発性の尿管ポリープであった。血清Ca, Pは正常範囲内であるがhypercalciuriaがみられ, %TRPも54%と低値で副甲状腺ホルモン値も高いため, 原発性副甲状腺機能亢進症を疑いcervical explorationを施行した。副甲状腺は, diffuse hyperplasiaを呈し3/4副甲状腺亜全摘術と胸腺摘出術を行った。摘出した胸腺内には異所性副甲状腺組織は認められなかった。文献的に本症候群には糖尿病, 甲状腺機能不全, 下垂体牲腺機能不全などのいくつかの内分泌機能障害が報告されている。しかし本症候群に副甲状腺機能充進を合併した報告は過去に1例をみるにすぎない。副甲状腺機能亢進症の診断上, %TRPと静脈カテーテルによる頸部静脈血のmultiple samplingによる副甲状腺ホルモン測定の意義について言及した。Herein is reported a case of 47 XXV-Klinefelter's syndrome associated with ureteral polyps, renal pelvic stone and primary hyperparathyroidism. To the best of our knowledge, this is the second patient reported to have Klinefelter's syndrome coexisting with primary hyperparathyroidism. Frequent endocrinological disorders in the patients with Klinefelter's syndrome and diagnostic problems for hyperparathyroidism and ureteral polyps are discussed

Effective Resistance Mismatch and Magnetoresistance of a CPP-GMR system with Current-Confined-Paths

We theoretically study the magnetoresistance of a CPP-GMR system with current confined paths (CCP) in the framework of Valet-Fert theory. The continuity equations for charge and spin currents are numerically solved with the three-dimensional CCP geometry by use of finite element method. It is confirmed that the MR ratio is enhanced by the CCP structure, which is consistent with the experimental results. Moreover, we find that there exists a certain contact width which maximize the MR ratio. We show that the contact width which maximize the MR ratio is well described by the effective resistance matching.Comment: 4 pages, 4 figure

Simulation of current-induced microwave oscillation in geometrically confined domain wall

We studied magnetization dynamics of a geometrically confined domain wall under dc current by solving simultaneously the Landau-Lifshitz-Gilbert equation and diffusion equation for spin accumulation. We showed that the oscillation motion of the domain wall is driven by the spin-transfer torque and the dc current is converted to the ac voltage signal. The results means that the geometrically confined domain wall is applicable as a source of microwave oscillator.Comment: 3 pages, 3 figure