RESEARCH INTERESTS:

Keywords: Materials Chemistry, Inorganic Chemistry, Solid State Chemistry, Oxide Chemistry, Magnetism and Physical Properties of Solids

Introduction:
Solid State Chemistry encompasses a multitude of materials with applications as electronic, magnetic, optical and catalytic. Polycrystalline materials are particularly important because the often straight forwared sample preparation (often solvent free) and because laboratory size badges can be scaled up for industrial processing. Oxides provide a wealth of structures and properties using multivalent cations, ordered and disordered structures are often very stable and can adapt a large number of structures while varying oxidation states and thus manipulating the electronic structure of these solids.

Our research group focuses on the preparation of novel inorganic solids and the investigation of their physical properties in an attempt to establish structure - property relationships. The materials of concern belong to the groups of transition metal oxides, lanthanide oxides and metal oxychlorides. It is particularly intriguing to focus on simple solids with, if possible only one paramagnetic ion and otherwise diamagnetic cations and anions. exhibiting interesting magnetic and physical properties. The principal tools for the investigation of new solid structures are powder X-ray diffraction and powder neutron diffraction. The investigation of physical properties, crystallographic structures and electronic structures allows the identification of structure-property relationships in solids. A systematic investigation can enable us to alter materials and their properties in a controlled fashion and therefore tailor specific materials.

Preparation of New Materials:
The research includes the preparation of polycrystalline oxides and oxychlorides using high temperature synthesis as well as low temperature sol-gel preparation techniques. Single crystals are grown from flux. The synthesis may be carried out in air, reactive gas atmospheres, inert gases, in vacuum or in sealed reaction containers. A large variety of synthetic methods can be employed for the preparation of solids.

Structural Characterization and Physical Properties:
The principal structural characterization tool is powder diffraction. The diffraction experiments include powder X-ray diffraction experiments using laboratory X-ray sources as well as synchrotron sources. Particularly important is the use of powder neutron diffraction experiments for the determination of oxide structures. The physical property measurements include magnetic susceptibility and magnetization measurements, as well as heat capacity and resistivity measurements etc.

Magnetic Structures:
The determination of magnetic structures are carried out using powder neutron diffraction. Muon spin relaxation measurements will be used for short range ordered and glassy magnetic systems. The investigation of magnetic structures includes long range magnetic ordering at low temperatures for non-frustrated as well as for frustrated magnetic sublattices. Also the investigation of magnetic short range ordering is being carried out. Some of these systems show exotic magnetic ground states due to competing exchange interactions.

last update: August 23, 2015