Unraveling the magnetic ground-state in alkali-metal lanthanide oxide Na${}_2$PrO${}_3$

Abstract

A comprehensive set of muon spin spectroscopy and neutron scattering measurements supported by ab-initio and model Hamiltonian simulations have been used to investigate the magnetic ground state of Na${}_2$PrO${}_3$. $\mu$SR reveals Néel antiferromagnetic order below $T_{\mathrm{N}}\sim 4.9$ K, with a small static magnetic moment $m_{\mathrm{static}}\le 0.22$~${\mu }_{\mathrm{B}}/\mathrm{Pr}$ collinearly aligned along the $c-$axis. Inelastic neutron measurements reveal the full spectrum of crystal field excitations and confirm that the Pr${}^{4+}$ ground state wave function deviates significantly from the ${\Gamma }_7$ limit relevant to the Kitaev model. Single and two magnon excitations are observed in the ordered state below $T_N=4.6$ K and are well described by non-linear spin wave theory from the Néel state using a magnetic Hamiltonian with Heisenberg exchange $J=1$ meV and symmetric anisotropic exchange $\Gamma /J=0.1$, corresponding to an XY model. Intense two magnon excitations are accounted for by $g$-factor anisotropy $g_{\mathrm{z}}/g_{\pm }=1.29$. A fluctuating moment $\delta m^2=0.57(22)$ ${\mu }_{\mathrm{B}}^2/\mathrm{Pr}$ extracted from the energy and momentum integrated inelastic neutron signal is reduced from expectations for a local $J=1/2$ moment with average $g$-factor $g_{\mathrm{avg}}\approx 1.1$. Together, the results demonstrate that the small moment in Na${}_2$PrO${}_3$ arises from crystal field and covalency effects and that the material does not exhibit significant quantum fluctuations..

References in corpus (40)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Kitaev-Heisenberg Model on Honeycomb Lattice: Possible Exotic Phases in Iridium Oxides $A_2$IrO${}_3$
• Kitaev quantum spin liquid - concept and materialization
• $\alpha$-RuCl3: a Spin-Orbit Assisted Mott Insulator on a Honeycomb Lattice
• Relevance of the Heisenberg-Kitaev model for the honeycomb lattice iridates A_2IrO_3
• Neutron tomography of magnetic Majorana fermions in a proximate quantum spin liquid
• Generic spin model for the honeycomb iridates beyond the Kitaev limit
• musrfit: A free platform-independent framework for muSR data analysis
• The monoclinic crystal structure of $\alpha$-RuCl${}_3$ and the zigzag antiferromagnetic ground state
• Critical exponents and equation of state of the three-dimensional Heisenberg universality class
• Orbital order and fluctuations in Mott insulators
• Pseudospin exchange interactions in d^7 cobalt compounds: Possible realization of the Kitaev model
• Spontaneous Magnon Decays
• Kitaev interactions between j=1/2 moments in honeycomb Na2IrO3 are large and ferromagnetic: insights from ab initio quantum chemistry calculations
• Kitaev-Heisenberg Hamiltonian for High-Spin $d^7$ Mott Insulators
• Topological Magnons in Kitaev Magnets at High Fields
• Ferromagnetic Kitaev interaction and the origin of large magnetic anisotropy in $\alpha$-RuCl${}_3$
• Dynamical structure factor of triangular-lattice antiferromagnet
• Frustration and anisotropic exchange in ytterbium magnets with edge-shared octahedra
• Rethinking $\alpha$-RuCl${}_3$
• Materials design of Kitaev spin liquids beyond the Jackeli-Khaliullin mechanism
• PyCrystalField: Software for Calculation, Analysis, and Fitting of Crystal Electric Field Hamiltonians
• Playing quantum hide-and-seek with the muon: localizing muon stopping sites
• Antiferromagnetic Kitaev Interaction in $f$-Electron Based Honeycomb Magnets
• Kitaev materials beyond iridates: order by quantum disorder and Weyl magnons in rare-earth double perovskites
• Pseudo-Goldstone gaps and order-by-quantum-disorder in frustrated magnets
• Breakdown of magnetic order in the pressurized Kitaev iridate $\beta$-Li${}_2$IrO${}_3$
• Neutron scattering and muon spin relaxation measurements of the non-centrosymmetric antiferromagnet CeCoGe3
• Chemical Design of Electronic and Magnetic Energy Scales in Tetravalent Praseodymium
• DFT+μ: Density Functional Theory for Muon Site Determination
• Toward the computational prediction of muon sites and interaction parameters
• Magnon interactions in the frustrated pyrochlore ferromagnet Yb${}_2$Ti${}_2$O${}_7$
• Collective excitations in the tetravalent lanthanide honeycomb antiferromagnet, Na2PrO3
• Computational design of $f$-electron Kitaev magnets: honeycomb and hyperhoneycomb compounds $A_2$PrO${}_3$ ($A=$ alkali metals)
• Muon contact hyperfine field in metals: A DFT calculation
• Long- to short-range magnetic order in fluorine-doped CeFeAsO
• Antiferromagnetic Kitaev Interactions in Polar Spin-Orbit Mott Insulators
• Honeycomb rare-earth magnets with anisotropic exchange interactions
• Disentangling superconducting and magnetic orders in NaFe_1-xNi_xAs using muon spin rotation

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