Mechanical and electrical properties of multilayer nanocomposites obtaining by electrodeposition and sputtering
* Adam Tokarz, * Andrzej Wolkenberg, * Andrzej Bochenek, * Zygmunt Nitkiewicz, ** Adam Łaszcz, ** Hanna Wrzesińska, ** Tomasz Przesławski * Politechnika Częstochowska, Instytut Inżynierii Materiałowej, al. Armii Krajowej 19, 42-200 Częstochowa ** Instytut Technologii Elektronowej, al. Lotników 32/46, 02-668 Warszawa
Annals 1 No. 2, 2001 pages 246-249
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abstract There are reported the structural, mechanical and electrical characterisation of multilayer nanocomposites - superlattices. Two kind of superlattices were investigated: metallic Cu/Ni and ceramic TiN/NbN. Both were deposited onto (111) or (100) ntype Si wafers. Cu/Ni multilayers were electrodeposited from single bath under potential control. The polarisation data allowed to choose deposition potentials of Ni and Cu layers (fig. 1). The ceramic TiN/NbN structures were performed by reactive sputtering. The structural properties of multilayers were carried out by X-ray diffraction (figs 2, 3), SIMS (Secondary Ions Mass Spectroscopy) and ellipsometry. The hardness was measured using Vickers indenter with 5 and 10 grams load. A maximum of 80 GPa and 9 GPa is measured for ceramic and metallic composites respectively. The influence of number of bilayers and thickness of the superlattice period Λ (fig. 4) on the hardness were investigated (tab. 1, 2). The magnetoresistance (MR) measurements were made using conventional four-point Van der Pauw geometry. For metallic superlattices the magnetoresistance measured in the current-in-plane configuration, is dominated by the giant magnetoresistance (GMR) effect for (111) oriented structures (fig. 5) and by the anisotropic MR effect for superlattices without any preferential crystallographic orientation. However electrical transport in metallic multilayers is clear, we find the positive magnetoresistance in ceramic structures. The maximum percentage changes achieved 80% for structure containing 10(×1.38 nm TiN + 5.82 nm NbN) (fig. 6). This suppressing properties of the ceramic superlattices could allow to produce magnetic sensors that are resistant for friction (e.g. sensors of the movement).