Structure and Properties of Mg-Ni-Fe Based Nanaocomposite Prepared by Spark Synthesis

0177623 - UFM-A 20013271 RIV SIGLE NL eng C - Conference Paper (international conference)
Schneeweiss, Oldřich - Jirásková, Yvonna - Žák, Tomáš - Bezdička, Petr - Večerníková, Eva
Structure and Properties of Mg-Ni-Fe Based Nanaocomposite Prepared by Spark Synthesis.
SMARTON 5 Workshop: Functional Surfaces and Materials. Exploring the Vectorial World. Nijmegen: Katholieke Universiteit Nijmegen, 2001, s. 48.
[SMARTON Workshop: Functional Surfaces and Materials. Exploring the Vectorial World /5./. Maatsricht (NL), 15.11.2001-18.11.2001]
R&D Projects: GA ČR GV202/98/K002; GA ČR GA202/01/0668; GA MŠMT ME 209; GA AV ČR KSK1010104
Institutional research plan: CEZ:AV0Z2041904
Keywords : nanomaterials * magnetic properties * Mössbauer spectroscopy
Subject RIV: BM - Solid Matter Physics ; Magnetism

A composite based on 3d metals particles embedded in MgO matrix is a promising material for application in sensors using high magnetoresistance. We prepared Mg-Fe-Ni nanocomposite using spark synthesis of the pure Mg, and permalloy (Ni3Fe) electrodes. The magnetic separation and sedimentation treatments were used for separation of nanocrystalline parts from the as-prepared powders. In the as-prepared powder, a-Fe + g-Ni3Fe, Fe(Ni) in Mg, and FeO phases were determined using the Mössbauer phase analysis. Some of the phases were confirmed by the x-ray diffraction measurements. The TG/DTA results indicate presence nanoparticles of Fe-Ni hydrides and high adsorption capacity of moisture and air gases. Temperature dependence of magnetization shows spin-glass like behaviour of the sample. Transformation of the Fe(Ni) in Mg phase and the hydride phases into a-Fe + g Ni3Fe and simultaneously an increasing in FeO + MgO were observed after annealing in vacuum (10-3 Pa) or in the protective atmosphere (H2).
Permanent Link: http://hdl.handle.net/11104/0074542