AMORPHOUS MAGNETIC FILMS FOR NON-STORAGE APPLICATIONS

Des possibilités d'application, autres que pour l'enregistrement, des couches amorphes d'alliages terres rares-métaux de transition et métal de transition-métalloide sont présentées. On considère en particulier les dispositifs générateurs d'ondes acoustiques de surface dans lesquels les films amorphes peuvent servir à l'accord des paramètres du dispositif. Une utilisation possible des films comme senseurs thermiques est aussi présentée.Possible non-storage applications of amorphous films of the rare earth-transition metal and transition metal-metalloid alloys are presented. Particular attention is given to the surface acoustic wave devices in which amorphous films can serve to tune the device parameters. A possible utilization of these films as thermal sensors is also presented

Domain structures in "non-magnetostrictive" Co67Fe4Cr7Si8B14 wide ribbons

The domain structure of as-cast 60 mm wide ribbons of a "non-magnetostrictive" metallic glass was studied by means of SEM and computer-aided magnetooptic Kerr effect. Various types of domain structure were observed along the ribbon width. The comparison of the structure on the shiny and wheel sides of the ribbon showed that the wide stripe domains extend through the whole thickness of the ribbon. The changes of the surface domain structure with the applied magnetic field made it possible to conclude that this structure is rather connected to the magnetization of the interior domains than to their wall-associated fields. The nonhomogeneous heat transfer during the production of wide ribbons and the associated temperature gradients across the ribbon width lead to a distribution of directions and magnitudes of local axes of effective anisotropy. The observations of the domain structures proved to be a useful tool for mapping these distributions and domain topography even in a material with rather low magnetostriction

Crystallization and magnetic properties of CoNbBCu metallic glasses

Rapidly quenched alloy of nominal composition Co68Nb10B30Cu2 has been chosen as the parent material for nanocrystalline magnets exhibiting Curie temperature of the residual amorphous matrix much lower than room temperature. Characteristic feature of these magnets is that the created ferromagnetic crystals are embedded in the paramagnetic amorphous matrix for the measuring temperatures in their relatively very wide range between both Curie points of the residual amorphous matrix and the crystals. Crystallization and microstructural properties of a series of the nanocrystalline magnets produced at different temperature of annealing have been studied and the results obtained are shown. Similarly, basic magnetic properties of the nanocrystalline samples are also presented. The main conclusion drawn is that the magnets considered are suitable for the studies of magnetic properties of the crystals themselves and their mutual interaction through paramagnetic matrix, in particular