Abstract
The high-field magnetic properties and magnetic order of the gem mineral green dioptase Cu6[Si6O18]·6H2O have been studied by means of single-crystal neutron diffraction in magnetic fields up to 21 T and magnetization measurements up to 30 T. In zero field, the Cu2+ moments in the antiferromagnetic chains are oriented along the c axis with a small off-axis tilt. For a field applied parallel to the c axis, the magnetization shows a spin-flop-like transition at B∗=12.2 T at 1.5 K. Neutron diffraction experiments show a smooth behavior in the intensities of the magnetic reflections without any change in the periodicity of the magnetic structure. Bulk and microscopic observations are well described by a model of ferromagnetically coupled antiferromagnetic XXZ spin-12 chains, taking into account a change of the local easy-axis direction. We demonstrate that the magnetic structure evolves smoothly from a deformed Néel state at low fields to a deformed spin-flop state in a high field via a strong crossover around B∗. The results are generalized for different values of interchain coupling and spin anisotropy.
| Original language | English |
|---|---|
| Article number | 014427 |
| Journal | Physical Review B |
| Volume | 103 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 19 2021 |
Funding
We greatly acknowledge R. Wahle, S. Gerischer, S. Kempfer, P. Heller, and P. Smeibidl for their support at the HFM/EXED facility at the Helmholtz-Zentrum Berlin. O.P. acknowledges support by ICC-IMR, Tohoku University. S.E.N. acknowledges support from the International Max Planck Research School for Chemistry and Physics of Quantum Materials (IMPRS-CPQM). D.Y. was supported by KAKENHI from Japan Society for the Promotion of Science, Grant No. 18K03525 (D.Y.), and “Early Eagle” grant program from Aoyama Gakuin University Research Institute. G.M. thanks Y. Motoyama for useful correspondence. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This material is based upon work supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division. Powder x-ray diffraction measurements were conducted at the Center for Nanophase Materials Sciences (CNMS) (CNMS2019-R18) at the Oak Ridge National Laboratory (ORNL), which is a DOE Office of Science User Facility. This work was partly supported by the Deutsche Forschungsgemeinschaft, through ZV 6/2-2, as well as by the HLD at HZDR, member of the European Magnetic Field Laboratory (EMFL). We greatly acknowledge R. Wahle, S. Gerischer, S. Kempfer, P. Heller, and P. Smeibidl for their support at the HFM/EXED facility at the Helmholtz-Zentrum Berlin. O.P. acknowledges support by ICC-IMR, Tohoku University. S.E.N. acknowledges support from the International Max Planck Research School for Chemistry and Physics of Quantum Materials (IMPRS-CPQM). D.Y. was supported by KAKENHI from Japan Society for the Promotion of Science, Grant No. 18K03525 (D.Y.), and "Early Eagle" grant program from Aoyama Gakuin University Research Institute. G.M. thanks Y. Motoyama for useful correspondence. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This material is based upon work supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division. Powder x-ray diffraction measurements were conducted at the Center for Nanophase Materials Sciences (CNMS) (CNMS2019-R18) at the Oak Ridge National Laboratory (ORNL), which is a DOE Office of Science User Facility. This work was partly supported by the Deutsche Forschungsgemeinschaft, through ZV 6/2-2, as well as by the HLD at HZDR, member of the European Magnetic Field Laboratory (EMFL).