Probing the $J_{eff}=0$ ground state and the Van Vleck paramagnetism of the Ir${}^{5+}$ ions in the layered Sr${}_2$Co${}_{0.5}$Ir${}_{0.5}$O${}_4$

Abstract

We report a combined experimental and theoretical x-ray magnetic circular dichroism (XMCD) spectroscopy study at the Ir-$L_{2,3}$ edges on the Ir${}^{5+}$ ions of the layered hybrid solid state oxide Sr${}_2$Co${}_{0.5}$Ir${}_{0.5}$O${}_4$ with the K${}_2$NiF${}_4$ structure. From theoretical simulation of the experimental Ir-$L_{2,3}$ XMCD spectrum, we found a deviation from a pure $J_{eff}=0$ ground state with an anisotropic orbital-to-spin moment ratio ($L_x/2S_x$ = 0.43 and $L_z/2S_z$ = 0.78). This deviation is mainly due to multiplet interactions being not small compared to the cubic crystal field and due to the presence of a large tetragonal crystal field associated with the crystal structure. Nevertheless, our calculations show that the energy gap between the singlet ground state and the triplet excited state is still large and that the magnetic properties of the Ir${}^{5+}$ ions can be well described in terms of singlet Van Vleck paramagnetism.

References in corpus (24)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Twisted Hubbard Model for Sr2IrO4: Magnetism and Possible High Temperature Superconductivity
• Multiplet ligand-field theory using Wannier orbitals
• Excitonic Magnetism in Van Vleck-type d^4 Mott Insulators
• Efficient real frequency solver for dynamical mean field theory
• Local electronic structure and magnetic properties of LaMn0.5Co0.5O3 studied by x-ray absorption and magnetic circular dichroism spectroscopy
• Direct observation of electron doping in La0.7Ce0.3MnO3 using x-ray absorption spectroscopy
• Valence, spin, and orbital state of the Co ions in the one-dimensional Ca3Co2O6: an x-ray absorption and magnetic circular dichroism study
• Novel magnetism of Ir5+ ions in the double perovskite Sr2YIrO6
• Bands, resonances, edge singularities and excitons in core level spectroscopy investigated within the dynamical mean field theory
• Ba2YIrO6: A cubic double perovskite material with Ir5+ ions
• Novel magnetic state in $d^4$ Mott insulators
• NaIrO3 - A pentavalent post-perovskite
• Orbital reconstruction in nonpolar tetravalent transition-metal oxide layers
• New Evidence for a Low-Temperature Magnetic Ground State in Double-Perovskite Iridates with Ir5+(5d4) Ions
• The iridium double perovskite Sr2YIrO6 revisited: A combined structural and specific heat study
• Effective magnetic interactions in spin-orbit coupled $d^4$ Mott insulators
• On the possibility of excitonic magnetism in Ir double perovskites
• Doping-Induced Ferromagnetism and Possible Triplet Pairing in d4 Mott Insulators
• Model analysis of magnetic susceptibility of Sr${}_2$IrO${}_4$ - 2D $J_{\mathrm{eff}}$ = 1/2 Heisenberg system with competing interlayer couplings
• Structure and Properties of α-NaFeO2-type Ternary Sodium Iridates
• Long-range interactions in the effective low energy Hamiltonian of Sr2IrO4: a core level resonant inelastic x-ray scattering study
• Intricacies of the Co${}^{3+}$ spin state in Sr${}_2$Co${}_{0.5}$Ir${}_{0.5}$O${}_4$: an x-ray absorption and magnetic circular dichroism study

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• Single crystal growth and magnetism of Sr3NaIrO6 and Sr3AgIrO6: tracking the J = 0 ground state of Ir5+
• Quantum Criticality in a Layered Iridate
• Trigonal distortion in the Kitaev candidate honeycomb magnet BaCo2(AsO4)2