Objective It is of interest to follow the origin and development of crystallographic and magnetic ordering and their correlation in ultrafine metallic particles. Such correlations can be better evidenced in the aggregation of atoms of different species. The purpose of the project is to study these optics iron-rich ultrafine (5-20 nm) Fe-Ni and Fe-Mn particles. The possibility of freezing the high temperature states of the fcc lattice during the formation of aerosol particles by gas evaporation will be exploited. The study of these particles by means of different analytical techniques such as X-ray diffraction, TEM, PAC, Moessbauer spectroscopy and magnetic tests will allow to verify experimentally the Weiss hypothesis on the existence of two spin (ferro- and antiferromagnetic) states of iron-rich binary fcc alloys. This is of fundamental importance to enlighten the mechanisms of atom interactions in such crystal lattices.Experimental indications on the co-existence of ferro- and antiferromagnetic states in small iron particles have been recently obtained. Preliminary tests on ultrafine Fe-Ni and Fe-Mn particles show the presence of ferromagnetic and paramagnetic states in the fcc lattice. However, the possible antiferromagnetism of these particles can be well evidenced only by isolating the superparamagnetic contribution which overlaps the paramagnetic peak in the Moessbauer pattern.The main objectives of the project are, therefore, the separation of these superparamagnetic and paramagnetic effects, and, as additional basic information, the determination of the Neel point of the produced material. In addition, a rather complete morphological, structural and magnetic characterisation of the samples will be performed in view of their possible practical applications. In particular, detailed information on the size and composition of the particles will come from PAC measurements. The results of the research will be communicated in the course of scientific conferences and published in international scientific journals. Programme(s) IC-INTAS - International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union (INTAS), 1993- Topic(s) 3 - Chemistry Call for proposal Data not available Funding Scheme Data not available Coordinator Università degli Studi di Padova EU contribution No data Address Via Venezia 1 35131 Padova Italy See on map Total cost No data Participants (1) Sort alphabetically Sort by EU Contribution Expand all Collapse all Semenova Institute of Chemical Physics of the Russian Academy of Sciences Russia EU contribution No data Address 117334 Moscow See on map Total cost No data
