Study of strongly correlated electronic and magnetic systems

Abstract

This Research Plan aim at exploring several topics in the study of materials that display properties derived from the strong correlation between charge carriers as well as between magnetic moments. The proponents, which are part of the Physics Institute of UNICAMP, are: Group of Magnetic and Optical Properties of Solids (GPOMS), from the Quantum Electronics Dept. (DEQ) and Laboratory of Materials and Low Temperatures (LMBT), from the Condensed Matter Physics Dept. (DFMC).We propose to carry on studies on several superconducting and magnetic systems, having singlecrystalline, polycrystalline or amorphous structure. The systems that are exclusively magnetic include a variety of materials that can display mixed valence, Kondo lattice, giant magnetoresistance (manganites) and granularity effects at nanometer scale. The systems that are exclusively superconducting include high, as well as low, critical temperature materials, whose electrical, magnetic and optical properties will be studied by us. We plan to study topics on vortex dynamics, factors influencing the critical current, resistive transitions and Hall effect, the gap symmetry, and the effect of magnetic ion substitutions. In particular, the coexistence of superconductivity and ordered magnetic phases will be studied in some materials.We expect to get relevant results that can help us to correlate microscopic and macroscopic properties, by employing current theoretical models as well as developing new ones. In the experimental work we plan to use different sample preparation techniques and several characterization methods, such as: X-ray diffraction, calorimetry, AC and DC resistivity, AC and DC magnetic susceptibility, magnetization, Electronic Paramagnetic Resonance (EPR), microwave absorption, and Raman scattering. Finally, we hope this Project can also contribute to educate well skilled people on the mentioned research areas. (AU)