Spin-glass insulating ground state in Y$_{2}$Os$_{2}$O$_{7}$

4$d$/5$d$ transition-metal oxides can display many exotic physical properties due to the interplay between spin-orbit coupling (SOC), Coulomb interaction, crystal field effect, Hund's coupling, and lattice distortion. The magnetic ground state of systems with $d^{4}$ electronic configuration is under hot debate since the consensus between experiments and theories has not been achieved. A non-magnetic ground state is expected under the $J_{\mathrm{eff}}$ scenario in the presence of SOC. However, various ground states are observed in some $d^{4}$ systems (such as Ir$^{5+}$, Os$^{4+}$, and Ru$^{4+})$. In this talk, I will present our study on Y$_{2}$Os$_{2}$O$_{7}$ with nonmagnetic Y$^{3+}$ at A site which allows us to study the magnetism of Os$^{4+}$ ($d^{4})$ sublattice. Polycrystalline Y$_{2}$Os$_{2}$O$_{7}$ was synthesized by solid state reaction and was studied by measuring electrical resistivity, magnetic susceptibility, specific heat, and neutron powder diffraction. A spin-glass insulating ground state is observed in contrast to the long-range magnetic ordered state in Y$_{2}$Ru$_{2}$O$_{7}$.