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The effect of iron addition on the martensitic transformation (MT) and shape memory effect (SME) of the Ni 2 MnGa sputtered films was investigated. It was found that the constraint-aged films with more than 8.5 mol% Fe have two phases. MT temperatures monotonously decreased with increasing amount of iron addition, while the Curie temperature increased. The reversible two-way SME by the thermal change was confirmed for all constraint-aged films containing iron through the MT and its reversion. Furthermore, the SME by magnetic field was observed around the MT temperature on cooling for the films containing iron in which MT occurred within the ferromagnetic region. The strain change in a low magnetic field of 1 T became large for the films containing iron. The behavior is as expected from the MT induced by the low magnetic field.

The effect of iron and cobalt addition on the magnetic and shape memory properties of Ni 2 MnGa sputtered films was investigated. It was found that heat-treated films with more than 5.1 mol% Co have two phases. Martensitic transformation temperatures of the constraint-aged films decreased with the iron addition and increased with increasing cobalt content. The Curie temperature of the heat-treated films increased with increasing amount of iron or cobalt. The constraint-aged films containing iron and cobalt exhibited a two-way shape memory effect by heating and cooling.

The shape memory effect (SME) by magnetic field is interesting and important for physics and application. The Ni2MnGa films were deposited on a poly-vinyl alcohol (PVA) substrate with a radio-frequency (RF) magnetron sputtering apparatus using Ni52Mn24Ga24 or Ni52.5Mn22Ga25.5 target. After separating from the substrate, the films were heat-treated at 1073 K for 36 ks for homogenization and ordering. They were constrained in a silica tube and heated at 673 K for 14.4 and 57.6 ks. The two-way SME for each constraint-aged film was confirmed by thermal cycling. The shape change of film under magnetic field was observed at constant temperature between A s ∗ and A f ∗ , or M s ∗ and M f ∗ . Magnetic field was applied parallel to the film surface up to 5 T using a super-conductor magnet. These films showed the SME by magnetic field. The strain by magnetic field was dependent on the measurement temperature. At temperatures between M s ∗ and M f ∗ , the strain increased with increasing magnetic field and slightly decreased with decreasing magnetic field. The martensitic transformation was induced by the magnetic field up to 5 T, which corresponds to that observed by cooling down to about 4 K.

Compositional dependence of magnetic entropy change in Ni2+xMn1−xGa Heusler alloys was investigated experimentally. The largest entropy change ΔS=20.7±1.5 J/K kg in the magnetic field H=1.8 T was revealed in the Ni2.18Mn0.82Ga alloy at a magneto-structural phase transition temperature of Ts=333.2 K. Magnetic-field-induced structural phase transition was observed.

Several properties with a thermoelastic phase transformation, the so-called shape memory effect, were studied in rapidly quenchd melt-spun Ti50Ni50−xCux (x = 0–20 at.%). By taking account of the improvements in several characteristics such as the large ductility (i.e. 180° bending ability), narrow transformation temperature range δT( = Af − Mf) and high thermal energy conversion ability ν, it can be concluded that the merit and functional superiority of rapidly quenched melt-spun TiNiCu ribbon exist especially in the range of copper contents over 10 at.% in comparison with the conventionally manufactured (i.e. melting-mechanically worked) material.

N, O and C atoms are separately incorporated in very pure a-Si:H. It is found that the addition of N or O increases the dark conductivity σ d , the photoconductivity σ p , the density of charged defects and the photocurrent decay constant, while the addition of C does not appreciably increases them. On the other hand, the addition of N or O of the amount of around 5 × 10 20 cm −3 gives rise to no change in the spin density increase by light-soaking, while the decrease in both σ d and σ p becomes more prominent. These results can well be explained if we assume that some of N and O atoms are incorporated in forms of N 4 + and O 3 + respectively.

Ti 50 Ni 50 − X Cu X ( X = 0, 5 and 13) alloys were prepared by the rapid solidification method. Ribbon-shaped specimens were obtained. The crystallinity was investigated by X-ray diffraction and electron microscopy. The specimens had good crystallinity and a large preferred crystal orientation.

Mesure de la force de restauration lors de la transformation martensitique thermoelastique accompagnant une variation de temperature dans les plaques d'alliage Ni-49 et 50% at Ti. Influence de la geometrie de l'echantillon (forme et longueur)

Combined measurements of ESR, LESR and CPM were carried out both for annealed and light-soaked a-Si:H films with several different thicknesses. These measurements reveal that the increase in the defect density by light-soaking mainly comes from the bulk region. Moreover it was found that the density of neutral dangling bonds is increased remarkably by light-soaking, but the density of charged dangling bonds does not appreciably change. The characteristic energy of the Urbach tail is found to be increased slightly (2 ± 1 meV) by light-soaking. The density of photo-created neutral dangling bonds for the films with less contaminant is similar to that for the conventional films.