NSLS-II Seminar

The synthesis of new materials under conditions of high pressure and temperature has led to important advances in many fields such as superhard materials, conducting glasses, materials for hydrogen storage and high-temperature superconductors, to name a few.
High-pressure modifications of solid-state chemistry often involve the increase of cation coordination number and stabilization of higher valence states of transition metals; in favourable cases compounds can be recovered metastably to ambient conditions.
In this talk I will illustrate the structural and magnetic properties of the family of high-pressure compounds AMn7O12 (A=Na+,RE3+) with quadruple perovskite structure that have been proposed as a disorder-free model system to explore collective electronic phenomena like charge, spin and orbital ordering and multiferroic behaviour. These phenomena have been intensely investigated in RE3+1-xD2+xMnO3 doped manganites with simple perovskite structure, where the role of quenched disorder associated with chemical doping is difficult to establish