Dresden 2006 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MA: Magnetismus

MA 26: Electron Theory

MA 26.8: Vortrag

Donnerstag, 30. März 2006, 12:00–12:15, HSZ 401

Organic Antiferromagnets, Diluted Magnetic Semiconductors, and Iron — Novel Features in the Magnetism in Correlated Electrons — •Avinash Singh — Department of Physics, Indian Institute of Technology Kanpur — Institute for Physics, Humboldt University at Berlin

There has been renewed interest in correlated electron systems on triangular lattices, as evidenced by recent studies of antiferromagnetism, superconductivity and metal-insulator transition in the organic systems κ−(BEDT−TTF)₂ X, the discovery of "water superconductors" Na_x Co O₂ . y H₂ O, the observation of low-temperature insulating phases in some √3-adlayer structures such as K on Si[111], and quasi two-dimensional 120^∘ spin ordering and spin-wave excitations in Rb Fe (MoO₄)₂ and the multiferroic material Ho Mn O₃. The discovery of ferromagnetism in Mn-doped III-V semiconductors such as Ga_1−xMn_xAs, has led to considerable interest in these diluted magnetic semiconductors (DMS) in view of their potential applications such as optical isolators, magnetic sensors, non-volatile memories seamlessly integrated into semiconductor circuits etc. and the possibility of studying new magnetic cooperative phenomena such as spin-dependent tunneling, magnetoresistance, spin-dependent light emission etc. in semiconductor heterostructures arising from the new (spin) degrees of freedom. I will describe some novel features in the magnetism of these materials of current interest, and also discuss recent progress in our understanding of the classic strong-coupling problem of a band ferromagnet such as iron.