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Cs-Bi and Cs-Sb absorbed graphite samples (Cs-Bi/graphite and Cs-Sb/graphite) were synthesized and their high temperature chemical stabilities were tested up to 1500 °C by TG and analyzed by TEM-EDS for the development of Cs trap material in high temperature gas-cooled reactor (HTGR) fuel particles. It was observed that Cs was stabilized by Sb but not by Bi in the specimens after the TG test. A rapid weight loss from 800 to 1000 °C may be caused by evaporation of Cs (boiling point: 671 °C) was seen in the TG result of both specimens. Precipitated Cs-Sb substance in the graphite matrix were not resolved even after the 1500 °C heating. The chemical composition of the Cs-Sb was specified as Cs3Sb. The experimental results suggest that Sb have potential to be a Cs getter material in graphite matrix. Long term heating test should be performed to confirm adaptability of Sb for Cs trap material in HTGR fuel particles.

We report the development of a millimeter-wave electron-spin-resonance (ESR) measurement system at the University of Fukui using a 3He/4He dilution refrigerator to reach temperatures below 1 K. The system operates in the frequency range of 125–130 GHz, with a homodyne detection. A nuclear-magnetic-resonance (NMR) measurement system was also developed in this system as the extension for millimeter-wave ESR/NMR double magnetic-resonance (DoMR) experiments. Several types of Fabry–Perot-type resonators (FPR) have been developed: A piezo actuator attached to an FPR enables an electric tuning of cavity frequency. A flat mirror of an FPR has been fabricated using a gold thin film aiming for DoMR. ESR signal was measured down to 0.09 K. Results of ESR measurements of an organic radical crystal and phosphorous-doped silicon are presented. The NMR signal from 1H contained in the resonator is also detected successfully as a test for DoMR.

We have developed a millimeter-wave electron-spin-resonance (ESR) measurement system using a 3He-4He dilution refrigerator for the ultralow-temperature range below 1 K. The currently available frequency range is 125–130 GHz. This system is based on a Fabry-Perot-type resonator (FPR) that is composed of two mirrors. The frequency can be changed by adjusting the distance between the mirrors using a piezoelectric actuator installed at the bottom of the resonator. A homodyne detection system with an InSb detector is built into the low-temperature section of the 3He-4He dilution refrigerator; this system provides high sensitivity. Using this system, we performed ESR measurements on a Heisenberg quantum-spin chain—copper pyrazine dinitrate, Cu(C4H4N2)(NO3)2—over the temperature range from 6.6 down to 0.25 K. The ESR lines change continuously with decreasing temperature. Our results suggest that the ESR spectrum of copper pyrazine dinitrate may be useful as a temperature sensor for the very low-temperature range.

Polyphenylene-based hydrophilic–hydrophobic diblock copolymers were developed and used as ionomers in the catalyst layers (CLs) of polymer electrolyte membrane fuel cells. The introduction of aliphatic side chains into the polymer backbone provided high oxygen transport properties in the CLs and high overall performance of the fuel cells.

We have developed a millimeter-wave electron spin resonance (ESR) measurement system using a 3He- 4He dilution refrigerator for the ultralow-temperature range below 1 K. The currently available frequency range is 125–130 GHz. The frequency can be changed by adjusting the distance between the mirrors using a piezoelectric actuator. Using this apparatus, we performed ESR measurements on a Heisenberg quantum-spin chain - copper pyrazine dinitrate (CuPzN for short), Cu(C 4 H 4 N 2 )(NO3)2 - over the temperature range from 6.6 down to 0.25 K. The ESR lines shift continuously with decreasing temperature. The results suggest that the ESR spectrum of CuPzN is possibly useful as a temperature sensor below 1 K.

We have developed millimeter-wave Fabry-Perot type resonator (FPR) aiming for simultaneous electron-spin and nuclear-spin resonance (ESR/NMR) measurements at very low temperatures below 1 K. The flat mirror of FPR is fabricated using a gold thin layer in order to minimize disturbance to radio frequency wave for NMR. An optimum thickness of the gold layer by measuring $Q$ value is found. We have actually succeeded to detect both ESR and NMR at very low temperatures.

In order to control the state of qubits by a microwave pulse, the irradiation time and the amplitude have to be controlled precisely. We have developed a single-flux-quantum (SFQ) microwave chopper for high-speed switching of microwave pulses. The proposed chopper is composed of a DC/SFQ convertor, an SFQ switch, a PTL driver, and a superconducting low-pass filter (LPF). The chopper converts an input microwave, which is generated by an external microwave generator at the room temperature, into microwave pulses by using start/stop SFQ control signals. We designed and implemented a microwave chopper module, which can be attached to dilution refrigerators. SFQ chips were fabricated using the ISTEC 2.5 kA/cm2 Nb process. We tested the microwave chopper module at 4.2 K, and demonstrated that a 5-GHz microwave whose amplitude ranging from 0 μV to 150 μV can be chopped by the SFQ control signals.

To evaluate the anisotropy of single crystals with a size of several tens of micrometers, we develop a technique for measuring the local transport properties along both the ab -plane and the c- axis using microsize devices fabricated by a focused ion beam process. We applied this technique to identify the resistivity anisotropy ( γ ρ = ρ c / ρ ab ) of the iron-pnictide superconductor PrFeAsO 0.7 synthesized under high-pressure. The obtained value of γ ρ ∼ 120 at 50 K indicates the presence of strong anisotropy, which is comparable to the anisotropy measured by other methods. The weak temperature dependence detected for the normalized resistivity along the c -axis (less than 10% difference at 280 K and 50 K) suggests a peculiar interlayer transport mechanism for PrFeAsO 0.7 .

We have developed a millimeter-wave electron-spin-resonance (ESR) system for very low temperatures (T < 1 K) that can be employed for nuclear-magnetic-resonance measurements by using dynamic nuclear polarization. The system uses a Fabry-Perot resonator that works in the frequency range of 125 – 130 GHz and covers the temperature range of 0.09 – 6.5 K. We have performed ESR measurements in the frequency around 128 GHz by using Mn x Mg1-x O (x = 1.0 × 10-4) and free-radical samples of 1, 1-diphenyl-2-picrylhydrazyl (DPPH), because these samples have been proposed as field and sensitivity markers. Temperature dependence of the ESR signal intensity for Mn x Mg1-x O shows anomalies originating from magnetic order are found around 3.5 – 4 K. We estimate the sensitivity of the system for ESR detections to be 6 × 1013 spins/G at 5.8 K. Because DPPH shows no observable shift in the magnetic field, we propose it as a useful standard marker for ESR measurements at very low temperatures.

We have demonstrated 500-MHz operation with our high-speed magnetoresistive random access memory (MRAM). For the next-generation MRAM, reducing magnetization switching current and its distribution is very important for decreasing power consumption. We found that some cells showed both large switching current and large switching current distribution under repeated writing tests. Although some failure modes related to the switching current distribution among multiple cells caused by rotated or shifted magnetic properties have been reported, they do not explain the extraordinary properties of each cell. To determine the origin of these properties, we investigated the influence of magnetic tunnel junction (MTJ) edge concave and convex deformation observed in MRAM fabrication. We found that the edge deformation and changed switching process generated a magnetization vortex, causing large switching current in a simulation. The switching characteristics of MTJs with some MTJ edge structures were fabricated and their characteristics were evaluated. We revealed that the edge deformation causes both large switching current and large switching current distribution of each cell. These characteristics correspond with those observed in the MRAM evaluation. Because cell sizes will become smaller and deformation size will become relatively large in the future, controlling MTJ shapes will become increasingly important for developing next-generation MRAMs.

Bismuth telluride (Bi 2 Te 3 ) bulk material was prepared by a powder hot-extrusion technique. The microstructure, texture evolution, and deformation-induced lattice defects, as well as the effect of heat treatment on its microstructure and thermoelectric properties were investigated. As-extruded Bi 2 Te 3 compound was found to be characterized by a dynamically and statically recrystallized microstructure with fine-equiaxed grains and low dislocation density. The majority of boundaries in the extruded specimens were large-angle boundaries with average misorientation angles of more than 30°. There was no significant change in dislocation configuration, even after heat treatment at a temperature higher than the extrusion temperature. Moreover, the Seebeck coefficient and electrical resistivity of the extruded specimens could not be improved by annealing. Microstructural examinations indicated the existence of a deformation-induced stacking disorder with local atomic shift, which we term “phase disorder,” on the basal plane in the extruded Bi 2 Te 3 compound. The presence of this structural defect may be one of the main reasons for the slightly lower values of thermoelectric properties for the hot-extruded Bi 2 Te 3 compound, compared with a unidirectionally solidified specimen.

The high temperature deformation behavior of Mg single crystals was precisely investigated using orientation imaging microscopy. For this purpose, Mg single crystals of various orientations were tensile tested in vacuum at temperatures between 473 and 673 K. A strain rate of 4.2 × 10−4 s−1 was employed. The elongations to fracture depended strongly on crystal orientation, the lowest fracture strains being associated with multiple slip. Single crystals in which single slip was activated exhibited extended ductilities corresponding to more than 1.5 in true strain. The strong orientation dependence of the ductility can also be correlated with the ease of occurrence of dynamic recrystallization (DRX), which took place in the multiple-slip specimens. The role of twinning in the initiation of DRX is also discussed.

Temperature dependence of the frictional stress derived from the Hall–Petch relation for pure magnesium polycrystals was compared with the critical resolved shear stress for single crystals with orientation preferable for basal or, alternatively, non-basal slip systems. The presented results suggest that the non-basal slip plays dominant role in the room temperature plastic deformation of polycrystalline magnesium, which is in excellent agreement with the recent output of computer simulation of mechanical behavior of Mg and its alloys using viscoplastic self-consistent model [Acta Mater. 49 (2001) 4277].

The origin of anomalous ductility in Ti-Ni alloy systems has been investigated by using Ti 50 Ni 48 Fe 2 with tensile tests at wide temperature range about 200 to 800 K and TEM observations. The advantage of the alloy used is that there is no decomposition during tensile test at elevated temperature. Tensile stress-strain curve is divided into three types. Below 400 K tensile deformation behavior relates to stress and or strain induced martensitic transformation. Between 400 and 700 K serration is observed in stress-strain curve, which is derived from the formation of various deformation twins with rather large twinning shear. Anomalous ductility is attribute to the formation of these twins and increment of slip system. Above 700 K necking take place during tensile test and only dislocations are seen in the deformed specimen. However, type of burgers vector dose not change with deformation temperature throughout the present study.

Silicon wafers are used for production of most microchips. Various processes are needed to transfer a silicon crystal ingot into wafers. To ensure high surface quality, the damage layer generated by each of the machining processes (such as lapping and grinding) has to be removed by its subsequent processes. Therefore it is essential to assess the subsurface damage for each machining process. This paper presents the observation of subsurface cracks in silicon wafers machined by surface grinding process. Based on cross-sectional microscopy methods, several crack configurations are identified. Samples taken from different locations on the wafers are examined to investigate the effects of sample location on crack depth. The effects of grinding parameters such as feedrate and wheel rotational speed on the depth of subsurface crack have been studied by a set of factorial design experiments. Furthermore, the relation between the depth of subsurface crack and the wheel grit size is experimentally determined.

The liquid phase epitaxy (LPE) grown YBa/sub 2/Cu/sub 3/O/sub x/ (YBCO) thick films are characterized as a superconductive substrate in comparison with bulk YBCO single crystal substrates. We have focused on the study of the chemical treatments improving the [001] YBCO surface which is mechanically polished. The reaction of the YBCO surface with the HCl/absolute methanol solution is effective for removing damaged remnants on the surface without roughening. Resulting surfaces are precisely examined by observations of atomic force microscopy. The topographical image and its line profile have confirmed that [001] YBCO surfaces are terminated by a unique atomic layer. The chemical stability is also examined under the conditions that additional depositions are followed to form a multilayer structure for devices.

Microstrip resonators and filters have been fabricated, using liquid phase epitaxially grown YBa/sub 2/Cu/sub 3/O/sub x/ films on MgO[100] substrates. A microstrip resonator at 10.8 GHz with a YBCO ground plane shows unloaded Q values of 14200 at 77 K and 23300 at 40 K. A microstrip four-pole band-pass filter, with a midband frequency of 10 GHz and a fractional bandwidth of 2% shows an insertion loss less than 0.2 dB and a return loss better than 15 dB at 77 K. The nonlinear behavior of this filter was studied by inter-modulation distortion measurements. This filter shows relatively high power handling capabilities with a third-order intercept point of +65 dBm at 77 K.

Plastic behaviour of the β nickel-titanium alloys with nearly-equiatomic compositions, Ti-49.5, 50.0 and 50.5 mol%Ni, has been studied. The alloys were highly ductile due to dislocation glide at temperatures where the β-phase was in equilibrium. The ductility became largest at the lowest temperature in the stability range of the β-phase. The strain-rate vs. flow stress relations of easy-glide deformation in tensile testing and steady-state creep deformation satisfied the power law. Both of the deformations are associated with the dislocation glide which are likely to be controlled by the Peierls mechanism. A yield drop at the onset of plastic flow appeared only in the tensile deformation of Ti-50.5 mol%Ni, but not in Ti-49.5 and 50.0 mol%Ni alloys. Excess nickel atoms would exist as antistructure defects, which might be responsible for the yield point phenomena.

We examined the magnetic and writing properties of clad writing lines for magnetic random access memory (MRAM) devices. After fabricating them, we applied a magnetic field of 1.2 T to them at room temperature. We call this operation initialization. Initialization reduced the flop current deviation of the single magnetic tunnel junction toggle cells. We fabricated a 4-Mbit toggle memory array with the clad lines, using initialization. It exhibited a large operating margin and a reduced switching current.

Recent developments and experiments performed at the high-field laboratory of Tohoku University are described. We have (1) hybrid magnets which produce high fields up to 31.1 T, (2) liquid-helium-free superconducting magnets up to 11 T which are available continuously for more than a year, (3) a 20 T superconducting magnet, (4) pulsed field magnets up to 40 T by a 100 kJ bank and (5) repeating pulsed field systems up to 25 T, synchronized with a pulsed neutron source.

The magnetization processes of the spin-glass Fe 0.50 Mn 0.50 TiO 3 and the reentrant spin-glass Fe 0.65 Mn 0.35 TiO 3 have been measured in the magnetic field H swept with various sweep-rates between 0.050 T/s and 0.750 T/s at 4.2 K and ∼1.4 K. When H is swept up or down fast beyond a critical value of the sweep-rate, the anomalous jump-up and jump-down of the magnetization occurs towards the values of the field-cooled-magnetization. The jump-up or jump-down field of the magnetization changes depending on the sweep-rate and the temperature. It is demonstrated that the hysteresis related to the jump of the magnetization becomes small gradually with increasing the sweep-rate, which is opposite to the normal behavior that the response of spin systems is delayed for a fast sweep of H . We consider that these phenomena are closely related to the properties of the spin-glass state.

A number of recent works on intermetallic compounds in the Ti-Al system have concentrated on gamma-based TiAl, but Al{sub 3}Ti is especially attractive because of its low density and good oxidation resistance. However, Al{sub 3}Ti, with a low-symmetry tetragonal D0{sub 22} structure, exhibits less than 1% compressive strain in the temperature range of 298 K to 893 K, for which the primary deformation mode is ordered twinning. Therefore, its brittleness limits its practical application as a structural material. More recently, much work has been conducted on the transformation of crystal structure through the addition of ternary alloying elements to improve the ductility of Al{sub 3}Ti. In this study, the plastic deformation behavior of two-phase intermetallic compounds consisting of mainly L1{sub 2} phase and the second phases in Al-Ti-Cr system was investigated. As in the case of {alpha}{sub 2}/{gamma} two-phase TiAl compounds, the possibility of ductilizing two-phase intermetallic compounds based on L1{sub 2}-type (Al,Cr){sub 3}Ti was examined. The influence of pore formation, ingot cast structure and second phase morphology on ductility of the alloy was also examined.

A compact nonvolatile programmable switch (NVPS) using 90 nm CMOS technology together with perpendicular magnetic tunnel junction (p-MTJ) devices is fabricated for zero-standby-power field-programmable gate array. Because routing information does not change once it is programmed into an NVPS, high-speed read and write accesses are not required and a write-control transistor can be shared among all the NVPSs, which greatly simplifies structure of the NVPS. In fact, the effective area of the proposed NVPS is reduced by 40% compared to that of a conventional MTJ-based NVPS. The instant on/off behavior without external nonvolatile memory access is also demonstrated using the fabricated test chip.

Ultrafine Mn(II)-ferrites represented by Mn x Fe 3 − x O 4 (x = 0.19–0.84) were synthesized by hydrolysis of Mn 2+ , Fe 2+ , and Fe 3+ ions, followed by aging of the coprecipitate at 60 °C without any hydrothermal and heat treatments. Nearly spherical and uniform particles were formed, the average crystallite size of which ranged from 8 to 13 nm. The Mn 2+ substitution of the ultrafine ferrite was corroborated by a linear increase in the lattice constant with an increase in the Mn(II) content of the products. The Mossbauer spectra revealed that the superparamagnetic fraction was small in the samples at room temperature, and the ultrafine particles were almost ferrimagnetic. In the absence of Fe 2+ , the coprecipitation of Mn 2+ and Fe 2+ (the Mn(II)/Fe total mole ratio = 0.5) resulted in an amorphous compound, indicating that the Fe 2+ ions facilitate the formation of the spinel ferrite during neutralization of the metal ions. This effect of Fe(II) ions on the ferrite formation can be attributed to the formation of dark red complex cation composed of Fe(II), Fe(III) and Mn(II) as the intermediate into ferrite. The magnetic properties of the ultrafine ferrites at room temperature were also given.

Structure changes during pseudoelastic deformation of CuAlMn single crystals were investigated using in situ optical and high-voltage electron microscopy (HVEM). Several crystal orientations were investigated, from an irrational to 〈100〉 and 〈110〉 tensile axis and plane orientations in the case of thin foils. The composition of the alloy was chosen such as to obtain superelastic behavior at room temperature. Optical microstructures allowed to identify parallel plates at the beginning of the stress plateau, the number of which increased with strain. The stress/temperature phase diagram was established within the range of existence of γ ′ 1 and β ′ 1 . During in situ HVEM deformation in the 〈100〉 direction of γ ′ 1 plates nucleated on pre-existing ones. At later deformation stages 18R martensite was formed in stacks of narrow needles. The following crystallographic relationship was observed: [001] β 1 ∥[010] β ′ 1 , γ ′ 1 and [110] β 1 ∥[001] β ′ 1 , γ ′ 1 . A small permanent deformation observed after stress release was connected with the presence of residual martensite of a high random stacking fault density and consisting often of α ′ 1 , γ ′ 1 and β ′ 1 martensite layers. During deformation in the 〈110〉 direction a larger permanent deformation and a density of dislocations was observed.

Prominent features of acoustic emission (AE) are established during stage III of plastic deformation of the [110] oriented Cu-9 at. % Al single crystals. The increase of the AE-level, the appearance of typical narrow-band spectral components of about 500 kHz and the lowfrequency oscillations of AE activity with a period of about 6 s are discussed. The interpretation of the phenomenon observed is given on the basis of a concept of the dislocation dipoles dissociation having an avalanche-like character.

The effect of environment on the fatigue life, crack initiation and propagation have been a subject of extensive investigations and numerous discussions for a long time. The purpose of the present work is to examine the environmental effect on fatigue crack propagation in copper compact tension (CT) specimens which allow them to control the crack initiation site and to observe crack growth on a relatively large area. A special attention is given to the crack propagation behavior and to the crack growth rate.

Modern acoustic emission (AE) techniques with spectral analysis of power have been applied to single crystals of copper and Cu-AI deformed in tension. The features of AE corresponding to stages I, II and III of plastic deformation are described by parameters derived from the statistical treatment of the AE spectra. The behaviour in stages I and II is attributed to two mechanisms : dislocation escape at a free surface, breakaway from pinning points. The two materials studied differ more by the source activity than by the type of sources.

In order to elucidate the deformation mechanism of materials in abrasive wear process, scratching tests were carried out on the (111) face of Cu-14.7 at % Al single crystals and Σ13 b bicrystals with pyramidal indentor. In the scratching on the single crystals three kinds of scratching directions, [11 ¯2], [¯1¯12] and [¯110], were chosen. In the case of bicrystals, the [1 ¯21] and [1¯10] directions were adopted. After scratching the dislocation structure, slip trace patterns and surface profiles across the scratched track were examined. In addition, the dislocation distributions inside the crystals were revealed by successively removing thin layers and developing etch pits on the exposed surface.

The magnetic field-induced shift in chemical equilibrium was studied for the ferromagnetic hydride LaCo5Hx-hydrogen system. The hydrogen composition x, which was monitored via the magnetization of the hydride, was observed as a function of magnetic fields up to 14 T under a constant pressure of hydrogen at 313.2 K. The hydrogen composition is gradually changed by 50% from x = 1.88 to x = 0.96 as the applied magnetic field was changed from 2 to 14 T. A thermodynamic theory can explain this effect, taking the change in magnetic free energy into account.

The interaction between a fatigue crack and the mechanical twins which are generated in front of the crack tip has been investigated in a compact tension specimen of a Fe-30 wt.% Cr alloy crystal. Significant slip localization and resultant persistent-slip-band-like damage were found along the twin boundaries. It was frequently observed that the fatigue crack captured by the damaged twin boundaries was propagated along these.

Kinetic regularities in the dissociation of unstable subgrain boundaries and the evolution of disclination-dislocation ensembles in electrodeposited nickel under load are discussed with respect to a detailed analysis of acoustic emission and transmission electron microscopy data. Phenomenological models are suggested in order to describe the processes of dissociation of terminated subboundaries and evolution of disclination dipoles. Corresponding methods of statistical and autocorrelation analysis of acoustic emission are developed in order to compare theoretical conclusions with experimental results.

The thermoelastic martensitic transformation and the stress-strain behaviour associated with the transformation in manganese-rich Mn-Cu alloys have been examined by tensile testing using single crystals grown by the Bridgman method. In the case of the deformation below the martensitic transformation temperature, twinning deformation in f.c.t. martensite has preceded dislocation glide, and the strain due to twinning showed a shape-memory effect. Regarding the continuous lattice parameter change, which can be observed in the temperature region extending over 100 K below the transformation temperature, the twinning strain decreased gradually by increasing the deformation temperature. It is shown that the shape-memory strain can be estimated by assuming the configuration of the twin-related domains of the f.c.t. martensite. Just above the transformation temperature, a stress-induced transformation has been found in the tensile testing. The characteristics of the stress-induced transformation from cub...

Diffusional relaxation around B2O3 particles which occurs concurrently with the deformation of a surrounding Cu matrix is experimentally and theoretically analysed from the shape change of the particles. The originally spherical B2O3 particles in the Cu matrix become a liquid at high temperatures. Although plastic deformation of the Cu matrix induces the particle elongation, a relaxation process operates to suppress the elongation at high temperatures. This causes smaller aspect ratios of the liquid particles than those expected from applied tensile strains. The relaxation is caused by the diffusion of the matrix Cu atoms along the Cu-B2O3 interface under the driving force of the excess interface free energy. The activation energy of the interface diffusion is evaluated as 1.7 eV. The kinetics of the shape change of a liquid particle in a deforming matrix is formulated including the effect of the diffusional relaxation. The theoretical calculations explain the experimental results on the temperature and particle-size dependences of the change in the aspect ratio of the B2O3 particles.

Fatigue crack initiation and propagation were studied on compact tension specimens of pure copper single crystals having [110] tensile axis. Two stages of crack propagation were found in accordance with different dependence of crack length on the number of cycles: the first stage of accelerating growth and the second stage of steady-state motion. Phenomenological models describing an acceleration of crack growth on the first stage and a constant velocity on the second are suggested. It was also shown that during the first stage a crack moves directly along one of persistent slip bands (PSBs) and the propagation direction frequently changes during the second stage. This behavior can be explained semi-quantitatively in the framework of the Essman—Gosele—Mughrabi model of the PSB structure.

The role of a grain boundary (GB) in the fracture of metals has been a subject of interest and controversy for a long time. A dual effect of GB on crack initiation and propagation is still discussed. The GBs usually assist crack initiation and propagation. However, it can provide obstacle to the crack under certain circumstances. The purpose of the present work is to examine the effect of GB on fatigue crack propagation in copper compact tension (CT) specimens which allows one to control the crack initiation site and to observe crack growth on a relatively large area. Two kinds of bicrystals possessing a longitudinal planar {Sigma}9, A, or a random GB, B, were chosen in order to clarify the role of the GB structure.

A number of spectral parameters of acoustic emission measured on copper and copper-aluminum single and polycrystals have been analyzed with the aim to establish the mutual correlations between them. It has been shown that since there are no simple correlations between most of the AE spectral parameters, it is necessary to consider a set of certain parameters to the realistic characterization of spectrum as a whole. The minimum set recommended includes the maximum power (energy) density, central frequency, effective width of spectrum or median frequency and total power (energy).

Defect dynamics in copper single crystals is investigated using a modern acoustic emission technique including analysis of the shape and power spectra of individual pulses. Crystals with various tensile orientations providing different dislocation behaviors such as single and multiple glide, formation of cells and Lomer-Cottrell locks, etc., are examined. Features of AE corresponding to stages I, II and III of plastic deformation are discussed in terms of statistical treatment of spectral parameters. It is shown that the AE spectra are sensitive to the transitions of deformation stages. The results of AE analysis are discussed from the viewpoint of relationships between dislocation emergence to a free surface and dislocation breaking away from pinning points.

The relation between pseudoelastic behavior and the thermoelastic transformation has been studied by means of the measurements of stress-strain curves in the temperature range above and below the martensitic transition temperatures in so called shape memory alloys. Thermodynamical analysis for the pseudoelasticity associated with the stress-induced martensitic transformation has been briefly reviewed and in conjunction with the measurements of latent heat of transformation, the thermoelastic martensitic properties are discussed form a thermodynamic point of view. It was found that using the Clausius-Clapeyron equation concerning the stress-strain relation obtained by the experiments, the enthalpy change was calculated and agreed reasonably well with the experimental values. The importance of the measurement of latent heat of transformation was emphasized for the justification of thermodynamical analysis of the pseudoelasticity associated with the stress-induced martensitic transformation in the shape memory alloys.

The anisotropic magnetoresistance (MR) effect, galvano- magnetic electromotive force effect, and forced MR effect in Ni-Fe thin films were studied by using high magnetic fields up to 15 T. These effects were measured in Ni-Fe thin films with various Ni compositions. The quantitative investiga- tion of the anisotropic MR effect and forced MR effect indicated that the dependence of the composition on the characterization of the anisotropic MR effect was similar to that of the forced effect. It was also found that the composition‘s dependence on the characterization of the forced effect had an additional peak around Ni0.5Fe0.5,which was not observed in the composition dependence of the anisotropic MR effect.

The stress-strain behavior associated with the martensitic transformation in the Cu-15.0 at.% Sn alloy has been examined thermodynamically. Tensile tests using single crystals showed that the successive martensite-to-martensite transformation can be induced under the applied tensile stress and is observed as a multi-stage stress-strain curve. The entropy change and the latent heat of stress-induced martensitic transformation were estimated from the calculation taking the dissipative energy of transformation into account. It will be shown that the dissipative energy contributes the decrease in the heat of the forward martensitic transformation and the increase in that of the reverse transformation. The calculated value is in good agreement with that measured by the differential scanning calorimeter. The dependence of the critical stress to induce martensite on the orientation of tensile axis has been examined, and it can be successfully explained by the orientation dependence of the mechanical driving force by the applied stress.

The effect of aging on pseudoelasticity in a shape memory alloy was studied using single crystals of a CuSn alloy, in which the martensitic transformation behaviour is fairly susceptible to an aging treatment. The aging effect on the nucleation of martensite was investigated in the specimens aged in the parent phase. The effect on the growth of martensite was studied by strain aging during tensile testing, and also by the analysis of strain rate dependence of pseudoelasticity. The former effect is attributed to the embryo exhaustion due to the diffusion of Sn atoms, originally proposed by Kennon. On the other hand the latter is explained from the pinning of a martensite/parent interface by the diffusion of Sn atoms.

High-speed capability and excellent reliability of a magnetic domain wall (DW) motion device required for embedded memory and logic-in-memory applications were achieved by optimizing the film stack structure of Co/Ni wire. Low-current with high-speed writing, high heat resistance, low error rate, wide operation range for temperature and magnetic field, high retention, and high endurance features were confirmed.

The lifetime of a water-cooled magnet is affected by dissolved oxygen in the cooling water. To analyze the relation between oxidation of a conductor and dissolved oxygen, the deposition of copper oxides and the electric resistance are measured for heated copper strips. The same measurements were done for a miniature Bitter coil. The lower the cooling water temperature, the more copper oxide deposited. The oxidation was more pronounced at the part near the water inlet than outlet. The oxidation was not observed in the experiment with nitrogen gas bubbling. In the actual water-cooled magnets with nitrogen gas bubbling, the magnets' lives are clearly extended. >

The shape memory properties of the TiNi alloy produced by a powder metallurgical method have been evaluated from tensile stress-strain curves. The contamination of the powders during atomization can be suppressed by applying the Plasma Rotating Electrode Process (P-REP), so that the compact made by Hot Isostatic Pressing (HIP) is expected to exhibit the shape memory effect identical to the typical alloy grown from melt. The fracture behavior of the P/M alloy is also studied, and the improvement of fracture strength of the P/M alloy is attempted.