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We investigated the effect of magnetic coupling (the energy constant of unit area: Jcpl) between CoFeB free layers on thermal stability factor Δ in Magnetic Tunnel junction (MTJ) with CoFeB/MgO double Interfacial Perpendicular Magnetic Anisotropy (IPMA). We newly introduced Jcpl in models for calculations, which were based on magnetic domain propagation model when MTJ diameter d is larger than critical diameter dc and magnetization coherent rotation model when d ≤ dc. With increasing Jcpl, Δ increases and saturates when Jcpl is over a critical value Jcpl_c. Magneto-static coupling constants (Jstat) between the free layers were also calculated. Jstat is so smaller than Jcpl_c and cannot maximize Δ by itself, that an interlayer exchange coupling (the critical energy constant of unit area: Jex_c) is required to cover the difference between Jcpl_c and Jstat. Jex_c also rapidly increases with the decrease of d and reaches a plateau of 0.15 mJ/m2 in d ≤ 30 nm. MTJ devices with a smallest Jex (=0.01 mJ/m2) and a moderate PMA (constant per unit area: Keff t*) were made and Δs were evaluated by experiments. The experimental Δs were fitted by the calculations with adjusting stiffness constants As. The calculated Δs and the experimental Δs were in good agreement when the As was a smaller value than that of the blanket film. Since the experimentally used Jex value was almost zero, Δ values were estimated when Jex was a greater value of 0.15mJ/m2. As a result, 30% enhancement of Δ was obtained at the smallest d = 20 nm.

We developed perpendicular magnetic tunneling junctions (MTJs) with four synthetic antiferromagnetically coupled Co/Pt layers (Quad-SyF) and investigated their magnetic and transport properties. The quad SyF comprised four Co/Pt layers and three 0.9 nm-thick Ru coupling layers, which consisted of Co/Co/Pta/Ru/Co/Co/Ptb/Ru/Co/Co/Ptc/Ru/Co/Co/Ptd from top to bottom. The exchange coupling field (Hex) reached a maximum of 1 T when the values of a, b, c, and d were 1, 2, 2, and 1, respectively. The tunnel magnetoresistance ratio of the MTJ with the Quad-SyF and the second-peak conventional Double-SyF increased as the annealing temperature was increased up to 400°C, whereas that of the MTJ with the first-peak conventional Double-SyF degraded at temperatures of more than 350°C in the blanket films. A 55 nm-diameter MTJ with Quad-SyF was found to be stable even against an external magnetic fields up to 300 mT. In contrast, in the conventional Double-SyF, the reference-layer magnetization direction flips at around 250 mT. The shift magnetic field of the MTJ with Quad-SyF becomes approximately zero when the values of a, b, c, and d were 1, 4, 1, and 2, respectively. No back-hopping of the MTJ with Quad-SyF was observed even for the write pulse width (tW) down to 10 ns. In contrast, an MTJ with conventional Double-SyF exhibited back-hopping. In the patterned MTJ with conventional Double-SyF, as the MTJ size decreases, the coercive field of Co/Pt significantly increases and Hex decreases, causing the m-H curve of the reference layer to cross the zero magnetic field. This enables both parallel and antiparallel configurations for the top and bottom Co/Pt layers in Double-SyF at the zero magnetic field, which could induce back-hopping. However, the m-H curves of the reference layer in the patterned MTJ with Quad-SyF are far from the zero magnetic field owing to the high Hex and low Hc, which could lead to the suppression of back-hopping.

We successfully developed 25-nm quad CoFeB/MgO-interfaces perpendicular magnetic tunnel junction (quad-MTJ) with enough thermal stability. To fabricate the quad-MTJ, a physical vapor deposition (PVD) process for depositing novel free layer and low resistance-area ( RA ) product MgO layer and low-damage fabrication processes were developed. The developed quad-MTJ technology and advanced process bring better tunnel magneto resistance (TMR) ratio and RA to quad-MTJ than those of double-interface MTJ (double-MTJ), even though quad-MTJ has an additional MgO layer. Scaling down the MTJ size to 25 nm, we demonstrated the advantages of quad-MTJ compared with double-MTJ as follows: 1) two times larger thermal stability factor ( $\Delta $ ), which results in over ten years retention; 2) superiority of large $\Delta $ in the measuring temperature range up to 200 °C; 3) ~1.5 times higher write efficiency; 4) lower write current at short write pulse regions at less than 100 ns; and e) excellent endurance of over 1011 thanks to higher write efficiency, which results from the reduced voltage owing to low RA and the low damage integration process technology. As a result, the developed quad-MTJ technologies will open the way for the realization of high-density STT-MRAM with low power, high speed, high reliability, and excellent scalability down to $2\times $ nm node.

The development of STT-MRAM technology is currently in progress and has been successively disclosed by major LSI vendors recently. In order to advance STT-MRAM technology and expand its areas of application, challenges relative to further device scaling need to be addressed. In this study, an increased wiring resistance in a deep sub-100 nm process by which the read operation yield is degraded was analyzed. The yield degradation was quantified by analyzing the conventional cell array using Monte-Carlo SPICE simulations. A new circuit was proposed to decrease the fail bit rate by an averaged reference voltage ( $V_{\mathrm {ref}}$ ) generator. The simulated results indicated that the new $V_{\mathrm {ref}}$ generator improved the fail bit rate by 1 order of magnitude compared to the conventional array. To demonstrate the circuit operation, a 128 Mb STT-MRAM chip was designed and fabricated using 40 nm CMOS and 37 nm MTJ technologies. For the first time, the chip measurements successfully demonstrated the operation of the proposed device-variation tolerant array architecture with the averaged $V_{\mathrm {ref}}$ generator, presenting a 30 ns read access time.

We fabricated a quadruple-interface perpendicular magnetic tunnel junction (MTJ) (Quad-MTJ) down to 33 nm using physical vapor-deposition, reactive ion etching, and damage-control integration process technologies that we developed under a 300-mm process. We demonstrated the greater scalability and higher writing speed of Quad-MTJ compared with double-interface perpendicular MTJ: 1) it has twice the thermal stability factor—1X nm Quad-MTJ can achieve 10 years retention—while maintaining a low resistance-area product and high tunnel magnetoresistance ratio; 2) smaller overdrive ratio of write voltage to obtain a sufficiently low write-error rate; 2) smaller pulsewidth dependence of the switching current; and 4) more than double the write efficiency at 10-ns write operation down to 33-nm MTJ. The effective suppression of the switching current increase for higher write speeds was explained by the spin-transfer-torque model using the Fokker-Planck equation. Our 33-nm Quad-MTJ also achieved excellent endurance (at least 1011) owing to its higher write efficiency and low-damage integration-process technology. It is thus a promising method for low power, high speed, and reliable STT-MRAM with excellent scalability down to the 1X nm node.

We investigated the influence of hard mask (HM) materials on tunnel magnetoresistance (TMR) properties and magnetic properties for the magnetic tunnel junctions with pependicular easy axis (p-MTJs) with double CoFeB/MgO interface annealed at 400 °C for 0.5–10 h. After annealing at 400 °C for 5 h, the TMR ratio of the MTJ with TiN HM was significantly decreased, whereas the TMR ratio of the MTJ with Ta-HM was maintained at a value of more than 120%. The analysis results by secondary-ion mass spectrometry (SIMS) and energy-dispersive X-ray spectroscopy (EDX) revealed that Ru in Ru-cap for the MTJ with TiN-HM diffused into the free layer through the MgO-cap layer, resulting in the degradation of the magnetic and TMR properties of the MTJ with TiN-HM. In contrast, Ru did not diffuse into the free layer for the MTJ with Ta-HM, which results from suppression of Ru diffusion into the free layer due to the formation of Ta–Ru alloy. Furthermore, in both the MTJs with TiN-HM and Ta-HM annealed at 400 °C for 10 h, EDX analysis revealed Pt diffusion into the CoFeB reference layer, which could degrade the magnetic properties of the reference layer, resulting in the degradation of TMR properties. To obtain a double CoFeB/MgO interface p-MTJ with higher thermal tolerance, it is necessary to design an HM material that suppresses the diffusion of the cap material into the free layer in addition to suppressing the Pt diffusion of the reference layer.

We have proposed a novel quad-interface magnetic tunnel junction (MTJ) technology which brings forth an increase of both thermal stability factor $\Delta $ and switching efficiency defined as the ratio of $\Delta $ to intrinsic critical current ${I}_{\text {C0}}$ ( $\Delta /{I}_{\text {C0}}$ ) by a factor of 1.5–2 compared with the conventional double-interface MTJ technology. The free layer of the developed quad interface consists of bottom-MgO/FL1/middle-MgO/FL2/top-MgO stack structure. We successfully fabricated the quad-interface MTJ using a 300-mm process based on a novel low-damage integration process including physical vapor deposition (PVD), reactive ion etching (RIE), and so on. By developing the quad-interface MTJ, we have achieved about two times larger $\Delta $ and $\Delta /{I}_{\text {C0}}$ at the same time. Moreover, we have achieved about two times larger tunnel magnetoresistance (TMR) ratio at the same resistance area (RA) product by developing the FL1, bottom-MgO, and middle-MgO. The developed quad-interface MTJ technology considered as post-double-interface MTJ technology will become an essential technology for the scaling of the spin-transfer-torque magnetoresistive random access memory (STT-MRAM) beyond 20 nm.

Measurement of intracellular calcium in live cells is a key component of a wide range of basic life science research, and crucial for many high-throughput assays used in modern drug discovery. Synthetic calcium indicators have become the industry standard, due their ease of use, high reliability, wide dynamic range, and availability of a large variety of spectral and chemical properties. Genetically-encoded calcium indicators (GECIs) have been optimized to the point where their performance rivals that of synthetic calcium indicators in many applications. Stable expression of a GECI has distinct advantages over synthetic calcium indicators in terms of reagent cost and simplification of the assay process. We generated a clonal cell line constitutively expressing GCaMP6s; high expression of the GECI was driven by coupling to a blasticidin resistance gene with a self-cleaving cis-acting hydrolase element (CHYSEL) 2A peptide. Here, we compared the performance of the GECI GCaMP6s to the synthetic calcium indicator fluo-4 in a variety of assay formats. We demonstrate that the pharmacology of ion channel and GPCR ligands as determined using the two indicators is highly similar, and that GCaMP6s is viable as a direct replacement for a synthetic calcium indicator.

We have studied the magnetic and electrical properties of double CoFeB–MgO interface magnetic tunnel junctions (MTJs) with various W insertion layer thicknesses $t_{\mathrm {W}}$ annealed at 400 °C and evaluated $t_{\mathrm {W}}$ dependence of thermal stability factor $\Delta $ , intrinsic critical current $I_{\mathrm {C0}}$ and damping constant $\alpha $ . It was found that spin-transfer torque efficiency ( $\Delta /I_{\mathrm {C0}}$ ) values increased with decreasing $t_{\mathrm {W}}$ as compared with the same MTJ size $D$ . $\alpha $ measured by ferromagnetic resonance increased with an increase in $t_{\mathrm {W}}$ , which is consistent with those calculated from $\Delta /I_{\mathrm {C0}}$ . This result indicates that lower damping constant of MTJ with thin W insertion layer contributes to higher $\Delta /I_{\mathrm {C0}}$ .

STT-MRAM is now an essential component for future low power consumption electronics. Recently, a number of STT-MRAM developments have been successively disclosed by major LSI vendors [1] –[9], and some of them announced that risk mass-production of STT-MRAM had started. This invited paper reviews, in this opportunity, STT-MRAM circuit design strategies, which cover memory cell design, sense amplifier (S/A) and reference generator (Refgen), and array architecture. Furthermore, as one example of STT-MRAM design, a 128Mb STT-MRAM chip using 40-nm standard CMOS and 3X-nm MTJ technology will be presented [10].

In last decade, since high performance MTJ using CoFeB/MgO-based interfacial perpendicular magnetic anisotropy (IPMA) is utilized, STT-MRAM technology has rapidly progressed and mass-production of STT-MRAM has already started in the semiconductor companies. However, for further expansion of MRAM applications and markets, higher reliability, larger capacity or speed are required. In this invited paper, we describe our recent progresses in STT-/SOT-MRAM fabricated under developed 300mm integration process (PVD, RIE etc.) [4] with advanced spintronics device technologies, such as quad-interface MTJ [10] and canted SOT device [12].

We have firstly fabricated quad-interface perpendicular MTJ (Quad-MTJ) down to 33 nm with our developed PVD, RIE and damage control integration process technologies under 300 mm process. Secondly, we demonstrated scalability merit as well as high speed writing of Quad-MTJ compared with double-interface p-MTJ (Double-MTJ) as follows; (a) two times larger thermal stability factor $\Delta(1\mathrm{X}$ nm Quad- MTJ is extrapolated to achieve 10 years retention.), (b) lower write voltage at short write pulse regions at less than 30 ns, (c) in scaled MTJ, effective suppression of write current increase for higher write speed, (d) more than 2 times higher write efficiency at 10ns write operation down to 33 nm MTJ. Finally, we revealed that our developed 33 nm Quad-MTJ achieve excellent endurance of more 1011 thanks to higher write efficiency and low damage integration process technology. These results show that the Quad-MTJ technology is one of promising way for low power, high speed and enough reliable STT -MRAM with excellent scalability down to 1X nm node.

When realising future fusion reactors, their stationary burning must be maintained and the heat flux to the divertor must be reduced. This essentially requires a stationary internal transport barrier (ITB) plasma with a fast control system. However, the time scale for determining the position of the foot point of an ITB is not clearly understood even though its understanding is indispensable for fast profile control. In this study, the foot point of the electron ITB (eITB) was observed to be reformed at the vicinity of a magnetic island when the island started to form. In addition, the enhanced confinement region was observed to expand during the eITB formation according to the radial movement of the magnetic island toward the outer region. Compared to the time scales of the local heat transport, the faster time scales of the movement of the eITB foot point immediately after island formation (~0.5 ms) suggest the importance of the magnetic island for plasma profile control to maintain stationary burning., 核融合エネルギーの実現に必要な水素プラズマの超高温領域を瞬時に拡大することに成功 --ゼロエミッションエネルギー実現に向けて前進--. 京都大学プレスリリース. 2020-01-09.

This study demonstrates a high-slew-rate 5-kV pulse generator for electrical insulation tests. Electrical equipment, such as electrical actuators and traction drive motors, are exposed to severe electrical stress because recent switching inverters have high-frequency outputs with high supply voltages using wide-bandgap power devices. For an advanced electrical insulation test, a high-voltage pulse generator is required with a high slew rate; however, such generators suffer from large switching noise, followed by measurement noise, such as ground voltage fluctuations and radiation noise, hindering the detection of partial discharge (PD) phenomena. In this study, we propose a 5-kV pulse generator based on series-connected 1700-V silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs). Four 1700-V SiC MOSFETs are connected in series as a 5-kV SiC switching module, constituting a half-bridge configuration for the pulse generator. The obtained switching waveforms exhibit fast rise times of 48 ns under 5 kV and 6.2 ns under 400 V with a low voltage overshoot and ringing owing to superior device characteristics and reduced parasitic inductances. Because of the low switching noise, we detect a clear PD signal with a 1500-V pulse when using the fabricated pulse generator for a PD test of a twisted pair. The proposed pulse generator uses a hard switching configuration such that the pulse generator can vary the pulse width from 150 ns to DC and increase the switching pulse cycle beyond 1 MHz by changing the control signals of the SiC MOSFETs.

We investigated an effect of sputtering gas species (Ar, Kr, and Xe) for deposition of a W insertion layer in the CoFeB/W/CoFeB free layer on magnetic properties of the free layer and tunnel magnetoresistance (TMR) ratio of magnetic tunnel junctions (MTJs) stacks using the free layer annealed at 400 °C for 1 h. As the W insertion layer thickness $t_{W}$ increased, we found the degradation of perpendicular anisotropy and larger reduction of saturation magnetic moment per unit area $m_{S}$ in the free layer using Ar compared to those using Kr and Xe. We also found a smaller TMR ratio for the MTJ stack using Ar compared to those using Kr and Xe. Energy-dispersive X-ray spectrometry line analysis revealed more significant interdiffusion between W and CoFeB layers in the free layer using Ar than those using Kr and Xe, that could result in the smaller $m_{S}$ and perpendicular anisotropy in the free layer and smaller TMR ratio for the MTJ stack using Ar than those using Kr and Xe. We also investigated concentration of Ar, Kr, and Xe in W layers deposited using Ar, Kr, and Xe, respectively, by high-resolution Rutherford backscattering spectrometry, revealing that 0.2 at% Ar was detected in the W layer using Ar, while Kr and Xe were not detected in W layers using Kr and Xe. Such a difference in concentration of inert gas atoms in the W layer could be one possible reason for the difference about degree of interdiffusion between W and CoFeB layers.

Structural stability of an environmental barrier coating (EBC) with thermal energy reflection function that has a periodic layered structure consisting of Y2Ti2O7 (YT) and Al2O3 is essential to maintenance of the EBC performance at high temperatures. The effect of adding Al to YT layer on the structural stability was investigated using model samples in which Al2O3 layer was formed on both the YT and Al-doped YT (AYT) substrate by aerosol deposition (AD). Exposure to heat selectively dissipated the Al2O3 layer on the YT substrate near the interface between the layer and the grain boundaries of the substrate. In contrast, the Al2O3 layer on the AYT substrate remained intact upon heating when Al was added at the solid solution limit. The Al2O3 layer was found to exhibit a pronounced degree of (0001) basal plane texture. An increase in the impact velocity of particles during AD effectively developed the basal fiber texture.

Background Currently, cryoballoon ablation (CBA) has proven to be highly effective in achieving free from atrial fibrillation (AF), especially paroxysmal AF. However, the optimal freezing protocol for each patient to achieve successful pulmonary vein isolation by only CBA is still uncertain. The aim of this study was to evaluate the clinical implications of a reduction in the freezing duration ( Methods From November 2015 to August 2018, 286 consecutive paroxysmal AF patients undergoing CBA were enrolled. We compared 107 patients undergoing a tailor-made CBA procedure (Group A; August 2017-August 2018) to 179 patients with a standard CBA procedure (Group B; November 2015–July 2017). In Group A, the freezing duration was reduced to 150s when the temperature reached ≤−40°C within 40s. Furthermore, we reduced it to 120s when it reached ≤−50°C within 60s. In the other patients, the freezing time was 180s except for excessive freezing over −60°C and/or emergent situations while monitoring the esophageal temperature and for phrenic nerve injury as in Group B. Results The baseline clinical characteristics were similar between two groups. In Group A, 89 patients (83%) underwent CBA with a reduction in the freezing time. The rate of having reduction time in left inferior PV (LIPV) and right inferior PV (RIPV) was lower compared with left superior PV (LSPV) and right superior PV (RSPV) (respectively 17%, 29%, 56%, and 63.5%). However, for right inferior PV, in 31 patients having the reduced freezing time, none of them required touch-up ablation. Although the procedure time and frequency of touch-up ablation did not differ between the 2 groups, total freezing time for each PV was significantly shorter in Group A than Group B as shown in figure (LSPV: 164±28s vs. 216±67s; p The freezing time for each PV Conclusion The safety and efficacy of the new tailor-made CBA strategy were non-inferior to the standard procedure. This study showed that the unnecessary freezing time could be reduced in most of paroxysmal AF patients.

Background Drug-eluting stent restenosis (DES-ISR) is associated with poorer outcomes than those of bare-metal stent restenosis after treatment with paclitaxel-coated balloon (PCB), and late restenosis after PCB angioplasty for DES-ISR is a residual problem. Excimer laser coronary angioplasty (ELCA) is thought to be advantageous for ISR treatment by removing neointima. However, whether the combination of ELCA and PCB angioplasty is more effective than the use of PCB only angioplasty in DES-ISR has not been studied so far. Purpose We evaluated the efficacy of ELCA and PCB combination therapy for DES-ISR at mid-and late-term after revascularization. Methods From January 2014 to March 2016, 166 DES-ISR lesions were treated with ELCA and no-ELCA prior to PCB. Two serial angiographic follow-ups were planned for the patients (at 6–12 and 18–24 months after procedure). Acute procedural and follow-up angiographic results were assessed by quantitative coronary angiography. ELCA and no-ELCA group included 74 lesions and 92 lesions, respectively. Results There was no significant difference between the two groups in the clinical characteristics except the prevalence of hemodialysis, the rate of first-generation DES (37.9% vs 36.8%, p=0.897), previous stent size (2.90±0.39 mm vs 2.77±0.39 mm, p=0.063), and reference vessel diameter (2.65±0.46 mm vs 2.60±0.65 mm, p=0.593). Early follow-up angiography was performed in 66 lesions (89.1%) of ELCA group, and was done in 76 lesions (82.6%) of no-ELCA group. In the ELCA group, percentage diameter stenosis (%DS) just after procedure and at 6–12 months later were significantly smaller than those of no-ELCA group. Besides, target lesion revascularization (TLR) rate at 6–12 months after procedure was tended to be lower in the ELCA group. Late follow-up angiography was performed for 93 lesions (81.6%) of the remaining 114 lesions (excluding TLR lesion), late restenosis was found 9 lesions (18.6%) in the ELCA group and 11 lesions (24.4%) in the no-ELCA group (p=0.504). Late luminal loss was similar in both groups (0.37±0.71 mm vs 0.24±0.82 mm, p=0.438), and %DS at 12–18 months after revascularization was not different between the two groups. Changes of %DS and TLR rate Conclusions %DS in the ELCA group was smaller at just after procedure and the advantage was kept even after 1-year. However, late restenosis and TLR at 2-year after revascularization for DES-ISR could not be reduced by ELCA and PCB combination therapy.

We have proposed novel quad-interface magnetic tunnel junction (MTJ) technology which brings forth an increase of both thermal stability factor $\Delta$ and switching efficiency $\Delta/I_{\text{C}0}$ by a factor of 1.5-2 compared with conventional double-interface MTJ technology. We successfully fabricated the quad-interface MTJ using 300mm process based on novel low damage integration process including PVD, RIE and so on [1]. By developing the quad-interface MTJ, we have achieved about two times larger $\Delta$ and $\Delta/I_{\text{C}0}$ . Moreover, we have achieved about two times larger TMR ratio/RA by the stack development specific for the quad-interface MTJ technology. The developed quad-interface MTJ technology regarded as post-double-interface MTJ technology will become an essential technology for the scaling of the STT-MRAM beyond 20nm.

Magnetic coupling between two CoFeB layers through the W insertion layer is important in the conventional double CoFeB/MgO interface, magnetic tunneling junctions (MTJs) (double-MTJs) with MgO/CoFeB/W/CoFeB/MgO free layer stack because it increases the effective magnetic volume of the free layer. The magnetic coupling energy constant per unit area, Jcpl, between two CoFeB layers through the W layer and the effective perpendicular magnetic anisotropy (PMA) energy constant per unit area, Kefft*, were investigated for conventional double-MTJs with various W insertion layer thicknesses. As the W layer thickness increased, Kefft* increased and Jcpl decreased. There exists a trade-off relationship between Jcpl and Kefft*. In conventional double-MTJs with a single W insertion layer, large values for Jcpl and Kefft* were difficult to obtain simultaneously. To improve this tradeoff, we employed a free layer stack with a thin ferromagnetic layer (ferromagnetic bridge layer: FBL) located in the W insertion layer. In the double-MTJs with FBL annealed at 400 °C, a large Jcpl value of 0.37 mJ/m2 was achieved while maintaining the maximum values of Kefft*. Accordingly, the MTJ with FBL provides an MTJ stack structure for obtaining high thermal stability.

The existence of a spatially varying texture in superfluid ^{3}He is a direct manifestation of the complex macroscopic wave function. The real space shape of the texture, namely, a macroscopic wave function, has been studied extensively with the help of theoretical modeling but has never been directly observed experimentally with spatial resolution. We have succeeded in visualizing the texture by a specialized magnetic resonance imaging. With this new technology, we have discovered that the macroscopic chiral domains, of which sizes are as large as 1 mm, and corresponding chiral domain walls exist rather stably in ^{3}He-A film at temperatures far below the transition temperature.

The development of the magnetic tunnel junctions with perpendicular easy axis using interfacial anisotropy [1–4] (p-MTJs) has been intensively advanced toward realization of high performance spin-transfer-torque magnetoresistive random access memories (STT-MRAMs). The p-MTJs used in the STT-MRAMs are required to withstand 400°C annealing to be compatible with CMOS back-end-of-line-process. Although we have demonstrated the thermal tolerance against 400°C annealing for the free layer in the CoFeB/MgO-based p-MTJs [5], we also found variation of properties in synthetic ferrimagnetic (SyF) reference layer. We revealed that the variation was caused by the diffusion of Fe in the CoFeB reference layer toward the bottom Co/Pt pinned layer after annealing [6]. We simultaneously observed degradation of perpendicular anisotropy of the Co/Pt multi layer. Perpendicular anisotropy of Co/Pt is influenced by the Co/Pt thickness ratio, buffer layer material, and roughness [7]. In this study, we focus on modification of the buffer layer and reveal that degradation can be suppressed by employing a surface modification treatment (SMT) of the Pt buffer layer. MTJ stacks from the substrate side, Ta /Pt buffer layer/with or without SMT/ [Co/Pt] 4 /Co /Ru/ [Co /Pt] 2 /Co /Ta /CoFeB /MgO barrier/free layer/top electrode, were deposited on a 300-mm $\Phi $ thermally oxidized Si wafer using a DC/RF magnetron sputtering system at room temperature (Fig.1(a)). In the SMT process, the Pt buffer layer was exposed to an ion plasma. The upper layers on the Pt buffer layer were deposited without breaking the vacuum. After deposition, samples were annealed at 350 °C for 2 h or 400 °C for 1 h in vacuum without applying magnetic field. The out-of-plane magnetic moment per unit area versus magnetic field (m-H) curves of the blanket films were measured by a vibrating sample magnetometer, and the film structures were investigated by energy dispersive x-ray spectroscopy (EDX) and high-resolution X-ray diffraction (HRXRD) using Cu Ka radiation. As shown in Fig. 1(b) and 1(c), perpendicular anisotropy of the SyF reference layer without SMT degraded after 400 °C annealing, while that of the SyF reference layer with SMT hardly changed. Interestingly, after annealing at 400 °C, magnetic moment variation in the top and bottom parts of the reference layer is observed in the stack without SMT due to Fe diffusion from the CoFeB reference layer toward the bottom Co/Pt layer, as we previously reported [6]. In contrast, the magnetic moments of the top and bottom parts of the reference layer in the stack with SMT are almost the same. This indicates that Fe diffusion in the reference layer is suppressed by the SMT of the Pt buffer layer. In order to verify this hypothesis, we performed cross-sectional EDX line analysis (Fig. 2). In the stack without SMT, Fe element in the CoFeB reference layer is observed in the other layers such as the top and bottom Co/Pt multilayers after annealing at 400 °C Fig. 2(a)), which indicates that Fe diffused toward the bottom Co/Pt layer. In contrast, in the stack with SMT, Fe element is observed only in the CoFeB layer in the as-deposited state and after annealing at 400 °C Fig. 2(b)). These results are consistent with the variation of magnetic properties shown in Fig. 1(b) and 1(c). In order to clarify the reason for the suppression of perpendicular anisotropy degradation of the Co/Pt multilayer after 400 °C annealing by SMT, we evaluated the crystal structure of the Co/Pt multilayer using HRXRD. X-ray diffraction analysis revealed that the ions penetrated the Pt buffer layer, expanding the Pt lattice constant and enhancing Co/Pt grain growth, which well oriented to the fcc (111) closed-packed plane parallel to the substrate surface. This caused larger perpendicular anisotropy in the Co/Pt multilayer and higher thermal tolerance. In addition, this may suppress Fe diffusion from the CoFeB reference layer toward the bottom Co/Pt layer. This work is supported by CIES’s Industrial Affiliation on STT MRAM program, and JST ACCEL Grant Number JPMJAC1301, Japan, and JST-OPERA.

The existence of a spatially varying texture in superfluid ^{3}He is a direct manifestation of the complex macroscopic wave function. The real space shape of the texture, namely, a macroscopic wave function, has been studied extensively with the help of theoretical modeling but has never been directly observed experimentally with spatial resolution. We have succeeded in visualizing the texture by a specialized magnetic resonance imaging. With this new technology, we have discovered that the macroscopic chiral domains, of which sizes are as large as 1 mm, and corresponding chiral domain walls exist rather stably in ^{3}He-A film at temperatures far below the transition temperature.

We developed a near-field etching technique for realizing an ultra-flat surfaces of various materials and structures. To elucidate the near-field etching properties, we have investigated the effects of power and the photon energy of the incident light. First, we established theoretically that an optical near-field with photon energy lower than the absorption edge of the molecules can induce molecular vibrations. We used nanodiamonds to study the power dependence of the near-field etching properties. From the topological changes of the nanodiamonds, we confirmed the linear-dependence of the etching volume with the incident power. Furthermore, we studied the photon energy dependence using TiO2 nanostriped structures, which revealed that a lower photon energy results in a lower etching rate.

The formation of an electron internal transport barrier (eITB) has been observed for the first time with centrally focused electron cyclotron heating (ECH) microwaves injected into plasma in Heliotron J. When the heating power per electron density (${P}_{\mathrm{ECH}}/{\bar{n}}_{{\rm{e}}}$) exceeds a threshold of $250\times {10}^{-19}\,\mathrm{kW}\,{{\rm{m}}}^{3}$, transient increases of both the central Te and the core Te gradients are observed. A neoclassical (NC) calculation using the Sugama–Nishimura moment method predicts that the large positive radial electric field (Er) is formed in the core region. Heat transport analysis shows a significant reduction of the effective electron thermal diffusivity in the plasma with the eITB related to that without the eITB. The large gap between the experimentally obtained effective thermal diffusivity and the NC thermal diffusivity suggests that the suppression of anomalous transport contributes to the core improved confinement of the eITB plasma. The electron cyclotron emission measurement shows both the transient increase and the hysteresis phenomena during the eITB formation.

The electrorheological (ER) fluid is a fluid that shows non-Newtonian fluid characteristics when the electrical field is applied. In this study, an experiment of an ER fluid viscous damper, in which an ER fluid is enclosed in the gap of a piston—cylinder system, is carried out to investigate the performances of the ER fluids and the effects of the electric field on the impulse response of the damper when an impulsive force is applied to it. To validate the experimental observations, a theoretical cylinder displacement formula of the damper is derived based on the Bingham approximation and the Stokes flow assumption of the test ER fluids in the damper. The present study shows that, when strength of the applied electric field and concentration of the ER fluids increase, the oscillation amplitudes of the cylinder displacement reduce. In other words, the ER damping effect is improved when the strength of the electric field increases.

Alkylphenols (APs), such as nonylphenol, are well-known as endocrine disrupting compounds (EDCs) and have been observed in aquatic environment. In this work, we focused on the rejection properties of NF membranes for APs. The rejection properties for 10 kinds of APs (alkyl group: C2–C9) were examined with four kinds of flatsheet-type NF membranes. The highest desalting membrane (Memb-1) effectively rejected 4-n-octylphenol and 4-n-nonylphenol at the rate of more than 95%, but the APs with lower molecular weight rejected at the lower degree. In the cases of lower desalting membranes, the rejections of the APs increased linearly with the increase of the molecular weight. The adsorption properties of the APs on the membranes were examined by both batch type adsorption experiments and an inverse HPLC technique. In the inverse HPLC experiments, polyamide particulates were used as the stationary phase and CH3OH/H2O (70/30) was used as the mobile phase. The logarithm of capacity ty factor (log k′) of the APs obtained by HPLC method was linearly correlated with the logarithm of the partition coefficient (log K) obtained by the batch type adsorption experiments. Since the log k′ was also correlated linearly with log P, it can be said that the adsorption properties of the APs on the membrane polymer were mainly controlled by the hydrophobic interaction.

Summary Background The level of the Dermatophagoides mite group 1 (Der 1) allergens in reservoir dust has been used as an index of exposure in most studies. However, the mite allergen level in reservoir dust cannot directly reflect the personal exposure level. Objective We sought to develop a new method for quantifying the Der 1 allergens on bedding and human skin surfaces as an index of exposure to mite allergens. Methods Samples were obtained with a small adhesive tape from the forearm skin of 30 healthy volunteers and from their regularly used mattresses. The level of Der 1 allergens collected onto the adhesive tape was measured by a newly developed sensitive fluorometric ELISA for Der p 1 and Der f 1. Results The Der 1 allergens could be detected in all the samples from bedding surfaces and in 28 of the 30 samples from skin surfaces. The Der 1 levels by adhesive tape sampling from the mattresses correlated with those by reservoir dust sampling. The sampling of the skin and bedding surface with adhesive tape correlated, but skin sampling did not correlate with reservoir sampling. Conclusion The Der 1 allergens on bedding surfaces and on human skin surfaces could be quantified with a very simple sampling technique. The system developed in this study will provide a new tool for the assessment of mite allergen exposure in daily life.

Objective. Fas-mediated apoptosis is preferentially observed in synoviocytes of patients with rheumatoid arthritis (RA) and is associated with the pathophysiological process of RA. To clarify the molecular mechanisms of Fas-mediated apoptosis of RA synoviocytes, we investigated the role of the mitochondrial pathway and tumour suppressor p53 in this process. Methods. Cultured synovial fibroblasts were prepared from RA patients. After treatment of RA synovial fibroblasts with anti-Fas monoclonal antibody, the expression levels of activated caspase-9 and -3, Bid cleavage, cytochrome c release and phosphorylation of p53 at Ser15 were assessed using immunoblot analysis. The mitochondrial membrane potential (m) was evaluated with a fluorescence-based detection assay. Apoptotic cells were determined by a DNA fragmentation assay in the presence or absence of caspase inhibitors. Expression of p53-regulated apoptosis-inducing protein 1 (p53AIP1) was measured by real-time PCR. RA synovial fibroblasts stably transfected with a dominant-negative (DN) p53 were prepared in order to investigate the role of p53 during Fas-induced apoptosis. Results. Fas ligation induced Bid cleavage, loss of m, cytochrome c release to the cytosol and activation of caspase-9 and -3 in RA synovial fibroblasts. Treatment with a caspase-9-specific inhibitor almost completely inhibited Fas-mediated apoptosis. Moreover, p53 activation after Fas ligation was evidenced by its phosphorylation at Ser15 and up-regulation of the p53 target gene p53AIP1. Fas-mediated apoptosis was significantly suppressed by anti-sense p53 oligonucleotides and by p53DN. Conclusion. Our findings strongly suggest the involvement of mitochondria and p53 in Fas-mediated apoptosis of RA synovial fibroblasts.

Anthralin (dithranol) is frequently used for the treatment of psoriasis. However, the mode of action of anthralin has not been completely elucidated as yet. Recent findings suggest that psoriatic keratinocytes are resistant to the apoptotic process. In this study, we examined the immunohistochemical expression of apoptosis-regulated protein in the involved psoriatic skin following topical anthralin therapy. Biopsy specimens were obtained from back skins treated with topical anthralin or white petrolatum (control) in 4 patients with psoriasis vulgaris. Immunohistochemical examination revealed that psoriatic keratinocytes expressed high levels of Bcl-x, which was significantly reduced after anthralin treatment. Bax was not detected in the epidermal keratinocytes in the petrolatum-treated skin, while it was present in the upper keratinocytes after anthralin therapy. Bcl-2 was detected only in basal layers of psoriatic epidermis following both petrolatum and anthralin application. Psoriatic keratinocytes expressed higher levels of Fas in the lower epidermis, while only weak expression was detected in anthralin-treated plaques. On the other hand, hyperproliferative keratinocytes strongly expressed Fas ligand (FasL) on their plasma membranes as well as infiltrating lymphocytes in the upper dermis. Furthermore, anthralin-treated psoriatic epidermis did not express FasL. In normal skin, keratinocytes expressed low to absent levels of Bcl-x and Bax, while Bcl-2 was detected only in melanocytes in basal layers. Neither Fas nor FasL were detected in the epidermis of normal skin. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) staining revealed positive labeling on the majority of psoriatic keratinocytes through the epidermis in petrolatum-treated skin, whereas anthralin treatment markedly reduced TUNEL-positive keratinocytes. These in vivo results may reflect improvement of the psoriatic skin following effective anthralin therapy.

Objective -- To report a case of idiopathic spinal epidural lipomatosis (SEDL) presented with unique radicular pain most likely caused by enlarged veins surrounding nerve roots. Patient A 26-year-old male presented with radicular pain of the right T6-T7 area. He also showed Becker's nevus in the corresponding area. CT myelography and magnetic resonance imaging revealed epidural lipomatosis posterior to T4 -T8 of the spinal cord. Surgical removal of adipose tissue and a hemilaminectomy of T4 T7 were performed and resulted in relief of the radicular pain. Conclusions Lipomatosis was histologically confirmed and surrounded by enlarged veins. These abnormally enlarged veins compressed the nerve roots and were thought to cause radicular pain. Also, Becker's nevus of this case seems to have some relationship with SEDL.

Approximately 20% of Beckwith-Wiedemann syndrome (BWS) cases are caused by mosaic paternal uniparental disomy of chromosome 11 (pUPD11). Although pUPD11 is usually limited to the short arm of chromosome 11, a small minority of BWS cases show genome-wide mosaic pUPD (GWpUPD). These patients show variable clinical features depending on mosaic ratio, imprinting status of other chromosomes, and paternally inherited recessive mutations. To date, there have been no reports of a mosaic GWpUPD patient with an autosomal recessive disease caused by a paternally inherited recessive mutation. Here, we describe a patient concurrently showing the clinical features of BWS and autosomal recessive cystinuria. Genetic analyses revealed that the patient has mosaic GWpUPD and an inherited paternal homozygous mutation in SLC7A9. This is the first report indicating that a paternally inherited recessive mutation can cause an autosomal recessive disease in cases of GWpUPD mosaicism. Investigation into recessive mutations and the dysregulation of imprinting domains is critical in understanding precise clinical conditions of patients with mosaic GWpUPD.

The fracture surface energy is calculated for a one-dimensional, exactly solvable model of a crack. The temperature dependence of the crack surface tension is determined on the basis of a self-consistent Einstein approach. It is found that lattice vibrations result in a strong reduction in the crack surface tension.