Synthesis and Characterization of bulk and Nano sheets of 4d and 5d based layered Transition Metal Oxides

Abstract

4d and 5d transition metal oxides (TMOs) crystallising in a honeycomb lattice and comprising of magnetic ions with strong spin-orbit coupling provide new avenues for current research in the condensed matter. Such TMOs with layered quasi 2- dimensional structures are even more interesting. This is due to the fact that layered TMOs can lead to experimental realization of graphene-like nanosheets with mag- netic honeycomb lattice. First part of this thesis deals with a new layered compound SrxCa1 xRu2O6, for which the parent SrRu2O6 has been theoretically predicted to exhibit topological states under strain. Here SrRu2O6 is a room temperature antifer- romagnetic insulator and hence important for device applications based on topological materials. Thus doping in the parent compound as well as formation of graphene -like sheets of the doped compound are possible approaches to tune the strain. The doped sample has been successfully synthesized by Hydrothermal route and characterized through Rietveld Profile Refinement of synchrotron X-ray di↵raction (XRD) data. The results of structural analysis reveal a clear anomaly in the lattice parameters near the room temperature. We have also conducted thermal di↵usivity measure- ments on the pressed pellet of the parent and the doped SrRu2O6, which confirm the possibility of change in thermal properties near the room temperature. Further to this, SrxCa1 xRu2O6 in the form of nanosheets has been obtained using the tech- nique of liquid exfoliation. These atomically thin nanosheets of parent as well as doped compound have been characterized through Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). In the second part of the thesis, the nanosheets of two Kitaev magnets Na2IrO3 and RuCl3 have been further characterized through TEM and AFM.