Novel Materials

Novel oxide materials such as manganites, nickelates, ruthenates, Invar and others with strongly correlated electrons and strong electron-phonon interactions are under theoretical and experimental investigation.

The outstanding results include a theoretical description of orbital liquids, magnetopolarons and magnetoresistance in manganites and ruthenates, and electronic phase separation.

The Kugel-Khomskii Hamiltonian originally introduced in the 1980s is playing a major role here. A highly cited novel theory of colossal magnetoresistance (CMR) in ferromagnetic oxides by Alexandrov and Bratkovsky (in collaboration with Hewlett-Packard Research Labs) is another remarkable achievement.

Alexandrov, Kabanov and Thomas are investigating how the de Haas-van Alphen and Shubnikov-de Haas magnetic oscillations are modified in nanostructures and other situations of reduced dimensionality.

Ziebeck, Brown and Neumann are working on various applications of polarised neutron scattering to resolve complex magnetic structures in Invar and other spin-Peierls materials. Their work has attracted substantial interest as a possible solution to the 100-year old Invar problem.

The ferromagnetic shape memory compound Ni2MnGa, first reported by Ziebeck, is currently attracting significant interest world wide, particularly regarding its potential applications. The development of this material is now a major research theme at many centres.