Hyperfine coupling in singlet ground state magnets

Abstract

The influence of hyperfine coupling to nuclear spins and of their quadrupolar splitting on the induced moment order in singlet ground state magnets is investigated. The latter are found among non-Kramers f electron compounds. Without coupling to the nuclear spins these magnets have a quantum critical point (QCP) separating paramagnetic and induced moment regime. The hyperfine interaction suppresses the QCP and leads to a gradual crossover between induced electronic and nuclear hyperfine coupling dominated magnetic order. It is shown how the critical temperature depends on the electronic and nuclear control parameters including the nuclear spin size and its possible nuclear quadrupole splitting. In particular the dependence of the specific heat on the control parameters and applied field is investigated for ferro- and antiferromagnetic order. It is shown that the three peak structure in the electronic induced moment regime gradually changes to a two-peak structure in the hyperfine coupling dominated nuclear moment order regime or for increasing field strength. Most importantly the possibility of a reentrance behaviour of magnetic order or likewise nonmonotonic critical fields due to hyperfine coupling influence is demonstrated. Finally the systematic evolution of the phase diagram under the influence of nuclear quadrupole coupling is clarified.

extended and published version, 15 pages, 12 figures

References in corpus (17)

• Frustrated two dimensional quantum magnets
• Complex Landau Ginzburg Theory of the Hidden Order in URu_2Si_2
• Direct bulk sensitive probe of 5f symmetry in URu2Si2
• Dual model for magnetic excitations and superconductivity in UPd2Al3
• Theory of induced quadrupolar order in tetragonal YbRu_{2}Ge_{2}
• Magnetic order and single-ion anisotropy in Tb${}_3$Ga${}_5$O${}_{12}$
• Singlet magnetism in intermetallic UGa${}_2$ unveiled by inelastic x-ray scattering
• f-Electron-Nuclear Hyperfine-Coupled Multiplets in the Unconventional Charge Order Phase of Filled Skutterudite PrRu4P12
• The role of hyperfine coupling in magnetic and quadrupolar ordering of Pr3Pd20Si6
• Limits to magnetic quantum criticality from nuclear spins
• Electro-nuclear transition into a spatially modulated magnetic state in YbRh${}_2$Si${}_2$
• Induced quantum magnetism in CEF singlet ground state models: Thermodynamics and excitations
• Induced order and collective excitations in three-singlet quantum magnets
• Quantum versus classical nature of a low-temperature magnetic phase transition in TbAl${}_3$(BO${}_3$)${}_4$
• Topological paramagnetic excitons of localized f electrons on the honeycomb lattice
• Paramagnetic electron-nuclear spin entanglement in HoCo2Zn20
• Magnetocalorics of singlet ground state induced moment magnets