Zak³ad III - Pó³przewodników - Laboratory of Amorphous and Nanocrystalline Metals

Laboratory of Amorphous and Nanocrystalline Metals

STAFF

prof. dr hab. Krystyna Pêka³a, tel.: 234 8214, pok.322, pekala(at)mech.pw.edu.pl - head
dr hab. in¿. Jerzy Antonowicz, tel.: 234 8214, pok. 322, antonowi(at)if.pw.edu.pl
mgr in¿. Przemys³aw Dziêgielewski, tel. 234 8231, pok. 326, pdziegielewski(na)if.pw.edu.pl

RESEARCH
Experimental studies of electronic and atomic structure of metallic amorphous and nanocrystalline solids

MAIN ISSUES
1. Electron transport processes in amorphous and nanocrystalline alloys.
2. Electronic, atomic and magnetic structures in amorphous and nanocrystalline solids.
3. Mechanisms and kinetics of nanocrystallization.

EXPERIMENTAL TECHNIQUES
Electron transport processes are studied by the electrical resistivity and thermoelectric power measurements between 100 and 1200 K.
The mechanisms and kinetics of nanocrystallization are analysed using synchrotron methods like X-ray diffraction (XRD) and simultaneous small- and wide-angle X- ray scattering (SAXS/WAXS).
The glass structure is investigated by X-ray absorption fine structure spectroscopy (XAFS). The amorphous alloys studied are prepared by a rapid quenching from a liquid phase, including the Al based nonmagnetic and the magnetic ones based on Fe, Co and Ni.

RESULTS

Defining the applicability range for various electron transport models in amorphous alloys.
Separation of electrical resistivity components due to the crystalline phase and amorphous matrix during crystallization.
Quantitative description of nanocrystallization transition by the specific nucleation mechanism and the crystal growth controlled by volume diffusion.
Determination of bond types existing in the amorphous material and cluster model of amorphous matrix verification.
Evidence for a strong interplay between the electronic structure, thermal stability, ability to nanocrystallization of amorphous alloys and the controlling mechanism of this process.
Derivation of the electron – phonon coupling constant from low temperature variation of thermoelectric power.
Separation of structural and magnetic components of electrical resistivity in ferromagnetic alloys.
Determination of the Debye and Curie temperatures from temperature variation of electrical resistivity.
A new method to analyse the nanocrystallization kinetics from X – ray diffraction data.
An evidence of the amorphous phase separation occurring in Al-based metallic glasses.
Model of nanocrystallization based on decomposition of the amorphous phase.
A modelling of phase content evolution during nanocrystallization using the temperature variation of electrical resistivity.

COOPERATION

European Synchrotron Radiation Facility (ESRF), Grenoble.

Laboratoire de thermodynamique et de physico-chimie métallurgiques, Institut National Polytechnique de Grenoble.

Department of Crystalline Materials Science, Nagoya University, Japan.

Institute of Physics, Slovak Academy of Sciences.

Faculty of Materials Science and Engineering, Warsaw University of Technology.

Faculty of Chemistry, University of Warsaw.

Department of Electronics, University of Mining and Metalurgy, Cracow.

Institute of Electronic Materials Technology, Warsaw.