Section of Condensed Matter Structure

Institute of Experimental Physics

Physics Faculty, University of Warsaw

   

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The Laboratory of Condensed Master Structure, headed by R. Przeniosło, was established in 2009. Most of the present group members were working (before 2009) in the Laboratory of Structure and Lattice Dynamics headed by I. Sosnowska (1981-2009). One of the most important achievements of the early days is the discovery of the modulated magnetic ordering in BiFeO3 described in [I. Sosnowska, T. Peterlin-Neumaier, and E. Steichele, J. Phys. C 15, 4835 (1982)]. This paper has more than 500 citations !

The team of the Laboratory of Condensed Matter Structure is using scattering methods to study the structure of materials with interesting physical properties including: magnetic materials, ferroelectrics-antiferromagnets and nanocrystaline materials. Our main research methods are based on neutron scattering and synchrotron radiation. We are using large scale facilities which provide neutron beams, e.g. ILL (Grenoble), SinQ (Villigen) ISIS (Chilton) as well as synchrotron radiation facilities ESRF (Grenoble). We are also using our in-house X-ray laboratory and materials characterization facilities in many collaborating institutions. The research efforts in the past few years (2009-2012) were concentrated on the following topics:

High resolution diffraction studies were used to obtain precise information about the modulated magnetic ordering in multiferroic compounds.

Our studies have shown an important magnetoelastic coupling in CaMn7O12 [2,5] which lead to a coexistence of the modulation of atomic positions [5,8] and modulation of the magnetic moments. These studies were performed in collaboration with the University of Manitoba (M. Bieringer), ILL Grenoble (E. Suard), ESRF (A. Fitch,) and the Inst. of Physics Czech Academy of Sciences (V. Petricek).

Studies of another multiferroic compound BiFeO3 provided information about the long range magnetic modulation in this material [3,7]. It was shown that the modulated magnetic ordering does not change its character in the temperature range from 300 K down to 5 K [3]. Recent high resolution SR diffraction studies [1] have shown a monoclinic distortion of the widely accepted rhombohedral BiFeO3 crystal structure. The studies are performed in collaboration with ILL Grenoble (A. Hewat), ESRF (A. Fitch) and ISIS, Oxon, Chilton, (A. Daoud-Aladine) UK and Tokyo Institute of Technology (M. Azuma).

The microstructure of nanocrystalline chromium (nano-Cr) was studied by SR diffraction and electron microscopy methods [4]. The time dependence of the grain growth process in annealed nano-Cr was studied by using high resolution SR diffraction [4]. Fast in-situ measurements provide information about the changes of the microstructure and also about the oxidation process. These studies were performed in collaboration with the University of Saarbruecken (R. Hempelmann) and ESRF (A. Fitch).



The temperature changes of the crystal structure of the mixed oxide CaCu3Ti4O12 showing colossal dielectric constant were studied by using high resolution SR diffraction. Our studies have shown some broadening of the X-ray diffraction peaks which may indicate a phase separation process or some anisotropic broadening. These studies were performed in collaboration with the University of Manitoba (M. Bieringer), ILL Grenoble (E. Suard), ESRF (A. Fitch).


 

 

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Last modification: 7 March 2012

 

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