Executive Summary : | Low dimensional spin systems have received a tremendous interest due to possible emergence of novel magnetic ground states such as quantum spin-liquid, 2D frustrated antiferromagnets, and spin gap formation. Among these, quantum spin-liquids are potential candidates for applications in the field of quantum computing and quantum information processing. Notably, the emergence of the quantum spin-liquid ground state is related to dynamic quantum fluctuations which are closely associated with a complex interplay of spin and orbital degrees of freedom. In this context, double perovskite oxides containing 5d elements, e.g., A2BIrO6 & A2BOsO6, has drawn significant research interest recently due to possibility of finding fascinating ground states such as quantum spin-liquid, Kitaev spin-liquid, unconventional superconductors etc., owing to strong spin-orbit coupling and complex-competing interactions of comparable energy scale, involving different degrees of freedom. Raman spectroscopy is very sensitive and powerful technique to probe magnetic ground states, interactions among various quasiparticles such as phonons, orbitons, magnons, polaritons, excitons, etc. and is widely used to study interactions among lattice, spin, charge, and orbital degrees of freedom. In this project, we choose to explore La2MIrO6 (M: Co or Ni), Ln2NiIrO6 (Ln = Lu, Gd), Ba2(Cu, Zn, Mg, Ca)OsO6, sr2CrOsO6, and Ca2FeOsO6 for possible interactions of phonons (lattice vibrations) with magnetic, transport, and dielectric properties using Raman spectroscopy. Further, we would like to explore the possible magnetostriction and correlation of phonons with thermodynamic phase transitions reported in Ba2(Zn, Mg, Ca)OsO6. In addition, we are interested in exploring spin ½ ladder (BiCu2PO6 and Pr2Ba4Cu7O15-δ) systems for novel magnetic ground states and superconductivity. We also would like to obtain and investigate magnetic 2D materials such MnPs3, NiPs3, and FePs3 as they are very promising candidates for spintronic applications. Overall, we obtain or synthesize above mentioned materials by solid state reaction and or or crystal growth techniques and characterize by structural, magnetic, transport, and thermodynamic measurements. Then, we plan to investigate them in terms of phonon related many body interactions using Raman spectroscopy. We will use DFT calculation results to validate experimental observations. |