Evidence for $J_{\mathrm{eff}}=0$ ground state and defect-induced spin glass behaviour in the pyrochlore osmate Y${}_2$Os${}_2$O${}_7$

Abstract

We present AC and DC magnetometry, heat capacity, muon spin relaxation ($\mu$SR) and resonant inelastic X-ray scattering (RIXS) studies of the pyrochlore osmate Y${}_2$Os${}_2$O${}_7$. We observe a non-zero effective moment governed by $\sqrt{f}{\mu }_{\mathrm{eff}}=0.417(1){\mu }_{\mathrm{B}}$ where $f$ is the fraction of Os sites which exhibit a spin, and spin freezing at temperature $T_{\mathrm{f}}\simeq 5$K, consistent with previous results. The field dependence of magnetisation data shows that the paramagnetic moment is most likely due to large moments ${\mu }_{\mathrm{eff}}\simeq 3{\mu }_{\mathrm{B}}$ on only a small fraction $f\simeq 0.02$ of Os sites. Comparison of single-ion energy level calculations with the RIXS data yields a non-magnetic $J_{\mathrm{eff}}=0$ ground state on the Os${}^{4+}$ sites. The spin-orbit interaction, Hund's coupling and trigonal distortion of OsO${}_6$ octahedra are all important in modelling the experimentally observed spectra. We are able to rule out impurity effects, leaving disorder-related effects such as oxygen non-stoichiometry or site interchange between Os and Y ions as the most plausible explanation for the magnetic response in this material.

References in corpus (19)

• Strong electronic correlations from Hund's coupling
• Excitonic Magnetism in Van Vleck-type d^4 Mott Insulators
• Novel magnetism of Ir5+ ions in the double perovskite Sr2YIrO6
• Muon Spin Relaxation Investigation of the Spin Dynamics of Geometrically Frustrated Antiferromagnets Y2Mo2O7 and Tb2Mo2O7 Static Critical Behavior of the Spin-Freezing
• Muon-spin rotation studies of SmFeAsO_0.85 and NdFeAsO_0.85 superconductors
• Ba2YIrO6: A cubic double perovskite material with Ir5+ ions
• Novel magnetic state in $d^4$ Mott insulators
• Emergent excitation at the magnetic metal-insulator transition in the pyrochlore osmate Cd2Os2O7
• Determination of Hund's coupling in 5d Oxides using Resonant Inelastic X-ray Scattering
• New Evidence for a Low-Temperature Magnetic Ground State in Double-Perovskite Iridates with Ir5+(5d4) Ions
• Lattice-Tuned Magnetism of Ru4+(4d4) Ions in Single-Crystals of the Layered Honeycomb Ruthenates: Li2RuO3 and Na2RuO3
• The iridium double perovskite Sr2YIrO6 revisited: A combined structural and specific heat study
• Unraveling the nature of magnetism of the 5${\mathbf{d}}^4$ double perovskite Ba${}_2$YIrO${}_6$
• Spin-orbit coupling controlled $J=3/2$ electronic ground state in 5$d^3$ oxides
• On the possibility of excitonic magnetism in Ir double perovskites
• Magnetism out of disorder in a J=0 compound Ba2YIrO6
• Diluted paramagnetic impurities in nonmagnetic Ba${}_2$YIrO${}_6$
• Robustness of superconductivity to competing magnetic phases in tetragonal FeS
• Fragile singlet ground state magnetism in pyrochlore osmates R2Os2O7 (R=Y and Ho)

Cited by in corpus (7)

• Spin-orbit-entangled electronic phases in 4$d$ and 5$d$ transition-metal compounds
• Kitaev Spin Liquid Candidate OsxCl3 Comprised of Honeycomb Nano-Domains
• Electronic excitations in $5d^4$ J=0 Os${}^{4+}$ halides studied by RIXS and optical spectroscopy
• Spin-orbit excitons and electronic configuration of the $5d^4$ insulator Sr${}_3$Ir${}_2$O${}_7$F${}_2$
• Ab initio determination of magnetic ground state of pyrochlore Y${}_2$Mn${}_2$O${}_7$
• Local site behavior of the 5d and 4f ions in the frustrated pyrochlore Ho2Os2O7
• Temperature-induced valence-state transition in double perovskite Ba2-xSrxTbIrO6