History
The Institute of Molecular Physics of the Polish Academy of Sciences in Poznan came into existence on the basis of the Poznan Division of the Physics Institute on April 3, 1975. However, the history of the Institute goes back more than 30 years to 1954, when the Ferromagnetic Laboratory, headed by Professor Szczepan Szczeniowski was founded. In 1956 the laboratory split into two units: the Ferromagnetics Laboratory of the Physics Institute headed by Professor Szczepan Szczeniowski and the Dielectrics Laboratory headed by Professor Arkadiusz Piekara. In 1966, the Dielectric Laboratory formed an independent Radiospectroscopy Laboratory headed by Professor Jan Stankowski.
Successively new research groups have been formed. At present, the Institute is composed of thirteen departments, dealing with the physics of dielectrics, physics of magnetics and radiospectroscopy.
Physics of Dielectrics, research in this field covers a range of problem concerning many substances, from liquids and very dilute solutions, liquid crystals, ferroelectric crystals and molecular crystals, ferro- and piezoelectric polymers, up to quasi-one-dimensional semiconductors, organic "metals" and organic superconductors. Methods of studies on the structure and molecular association of solutions have been developed. The unique method of dielectric saturation is applied to studies of systems with the proton transfer and critical phenomena in mixtures. Long range molecular order is investigated in liquid crystals, especially in ferroelectric smectics. These studies in pure substances and liquid crystal mixtures are primarily conducted by dielectric and optical methods. Studies on the mechanisms of phase transitions in crystals with long-range electric order are in progress. The influence of lattice defects on certain dielectric, electric and critical properties of feroelectrics, as well as the domain structure of the latter and its relation to the ferroelectric properties are studied. Theoretical studies of phase transitions are performed on model systems by computer simulation.
Investigations on the electrical, magnetic and spectroscopic properties of quasi-one-dimensional organic crystals are developed in the Institute. The physical properties of piezoelectric polymers and foil electrets are also studied, The technology of electret microphone, which is now used for commercial production, has been developed in the Institute.
Physics of Magnetism and Magnetic Materials, research in this field concerns the theory of magnetic properties of metals and alloys. Specific problems include band structure calculations of metals, and ordered and disordered alloys, itinerant electron ferromagnets at finite temperatures, phase transitions, effects of structural disorder, electron-phonon interaction, thin magnetic films and multilayers, in particular the exchange coupling through nonmagnetic interlayer, scattering of light on free electrons in metals, dynamic of electrons in quasistatic magnetic fields and quantum size effects. Among other problems studied are phase transitions in spin systems on fractal lattices. Research on magnetic alloys covers: the production technology of intermetallic compounds of rare earth with transition metals, permanent magnets on the basis of these compounds and the technology of amorphous and nanocrystalline layers of magnetic alloys. The following properties of these materials are studied: atomic ordering, magnetization as a function of temperature and external magnetic field, phase transformations, anisotropy, magnetostriction, domain structure. Experimental studies involve investigations of magnetic, galvanomagnetic and transport properties in connection with structural studies, covering a vast class of materials such as: metallic multilayers and superlattices, amorphous alloy films. The laboratory is presently focusing its work on magnetic anisotropies of magnetoelastic origin and galvanomagnetic phenomena.
Radiospectroscopy began with the project of ammonia maser and the NMR relaxation in flowing water. In solids, EPR of admixture ions are used to determine the electron and molecular structure of crystals, proton glasses, incommensurate phases and phases transitions. Spin-phonon interactions are also studied. The EPR method is applied to the studies of the electron structure of isolates and multi-core paramagnetic complexes and the coordination of paramagnetic ions in the ferroelectric crystals. Studies on crystal lattice dynamics lead to important data on modulated structures and soft modes in paramagnetic ion-doped ferroelectric crystals. Pressure effects in the one-dimensional organic salts are also investigated by EPR. The nature of the phase transitions in hexa-ammines is extensively investigated. Rotation of various molecular groups in liquids, organic polymers and crystals are investigated by NMR and NQR methods. Critical state of hydrogen bonds has been examined with the high-pressure NQR studies. The magnetic resonance pulse methods, dielectric investigations of helium, low-temperature thermometry are given a particular attention, Josephson-effect magnetic modulated microwave absorption (MMMA) was proposed as an independent characteristic of superconducting materials. Intermolecular interactions in the collision processes and effects of internal rotation in simple molecules are studied with the microwave Stark spectroscopy. The nature of paramagnetic centers in fullerenes is studied by the EPR method.
