Crystal-field states and defect levels in candidate quantum spin ice Ce${}_2$Hf${}_2$O${}_7$

Abstract

We report the synthesis of powder and single-crystal samples of the cerium pyrohafnate and their characterization using neutron diffraction, thermogravimetry and X-ray absorption spectroscopy. We evaluate the amount of non-magnetic Ce${}^{4+}$ defects and use this result to interpret the spectrum of crystal-electric field transitions observed using inelastic neutron scattering. The analysis of these single-ion transitions indicates the dipole-octupole nature of the ground state doublet and a significant degree of spin-lattice coupling. The single-ion properties calculated from the crystal-electric field parameters obtained spectroscopically are in good agreement with bulk magnetic susceptibility data down to about 1 K. Below this temperature, the behavior of the magnetic susceptibility indicates a correlated regime without showing any sign of magnetic long-range order or freezing down to 0.08 K. We conclude that Ce${}_2$Hf${}_2$O${}_7$ is another candidate to investigate exotic correlated states of quantum matter such as the octupolar quantum spin ice recently argued to exist in the isostructural compounds Ce${}_2$Sn${}_2$O${}_7$ and Ce${}_2$Zr${}_2$O${}_7$.

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Cited by in corpus (17)

• Quantum Spin Ice Response to a Magnetic Field in the Dipole-Octupole Pyrochlore Ce${}_2$Zr${}_2$O${}_7$
• Spectroscopic signatures of fractionalization in octupolar quantum spin ice
• $\mu$SR Study of the Dipole-Octupole Quantum Spin Ice Candidate Ce${}_2$Zr${}_2$O${}_7$
• Emergent photons and fractionalized excitations in a quantum spin liquid
• Distinguishing thermodynamics and spectroscopy for octupolar U(1) spin liquid of Ce-pyrochlores
• A pseudofermion functional renormalization group study of dipolar-octupolar pyrochlore magnets
• Finite Temperature Dynamics in 0-Flux and $\pi$-Flux Quantum Spin Ice: Self-Consistent Exclusive Boson Approach
• Linear scaling relationship of Néel temperature and dominant magnons in pyrochlore ruthenates
• Exploiting polarization dependence in two dimensional coherent spectroscopy: examples of Ce${}_2$Zr${}_2$O${}_7$ and Nd${}_2$Zr${}_2$O${}_7$
• Dipolar-octupolar correlations and hierarchy of exchange interactions in Ce${}_2$Hf${}_2$O${}_7$
• Two-Peak Heat Capacity Accounts for $R\ln (2)$ Entropy and Ground State Access in the Dipole-Octupole Pyrochlore Ce${}_2$Hf${}_2$O${}_7$
• Thermodynamics of the dipole-octupole pyrochlore magnet Ce${}_2$Hf${}_2$O${}_7$ in applied magnetic fields
• Signatures of spinon dynamics and phase structure of dipolar-octupolar quantum spin ices in two-dimensional coherent spectroscopy
• Single Crystal Diffuse Neutron Scattering Study of the Dipole-Octupole Quantum Spin Ice Candidate Ce${}_2$Zr${}_2$O${}_7$: No Apparent Octupolar Correlations Above $T=0.05$ K
• Easy-plane ferromagnetic ordering and crystal-field ground state in the Kondo lattice CeCuSi
• Towards a global phase diagram of Ce-based dipolar-octupolar pyrochlore magnets under magnetic fields
• Excitation spectrum and low-temperature magnetism in disordered defect-fluorite Ho2Zr2O7