Abstract
We present a comprehensive experimental investigation of Yb magnetic dimers in Yb0.04Y0.96AlO3, an Yb-doped yttrium aluminum perovskite YAlO3, by means of specific heat, magnetization, and high-resolution inelastic neutron scattering (INS) measurements. In our sample, the Yb ions are randomly distributed over the lattice and ∼7% of Yb ions form quantum dimers due to nearest-neighbor antiferromagnetic coupling along the c axis. At zero field, the dimer formation manifests itself in an appearance of an inelastic peak at Δ≈0.2meV in the INS spectrum and a Schottky-like anomaly in the specific heat. The structure factor of the INS peak exhibits a cosine modulation along the L direction, in agreement with the c-axis nearest-neighbor intradimer coupling. A careful fitting of the low-temperature specific heat shows that the excited state is a degenerate triplet, which indicates a surprisingly small anisotropy of the effective Yb-Yb exchange interaction despite the low crystal symmetry and anisotropic magnetic dipole contribution, in agreement with previous reports for the Yb parent compound, YbAlO3 [L. Wu, Nat. Commun. 10, 698 (2019)2041-172310.1038/s41467-019-08485-7, L. S. Wu, Phys. Rev. B 99, 195117 (2019)2469-995010.1103/PhysRevB.99.195117], and in contrast to Yb2Pt2Pb [L. S. Wu, Science 352, 1206 (2016)SCIEAS0036-807510.1126/science.aaf0981, W. J. Gannon, Nat. Commun. 10, 1123 (2019)2041-172310.1038/s41467-019-08715-y]. The obtained results are precisely reproduced by analytical calculations for the Yb dimers.
| Original language | English |
|---|---|
| Article number | 245150 |
| Journal | Physical Review B |
| Volume | 101 |
| Issue number | 24 |
| DOIs | |
| State | Published - Jun 15 2020 |
Bibliographical note
Publisher Copyright:© 2020 American Physical Society.
Funding
We acknowledge A. S. Sukhanov for stimulating discussions. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by Oak Ridge National Laboratory. S.E.N. acknowledges support from the International Max Planck Research School for Chemistry and Physics of Quantum Materials (IMPRS-CPQM). Laue x-ray diffraction measurements were conducted at the Center for Nanophase Materials Sciences (CNMS) (CNMS2019-R18) at Oak Ridge National Laboratory (ORNL), which is a DOE Office of Science User Facility. The work at Brookhaven National Laboratory was supported by Office of Basic Energy Sciences (BES), Division of Materials Sciences and Engineering, US Department of Energy (DOE), under Contract No. DE-SC0012704.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | DE-SC0012704 |
| Basic Energy Sciences | |
| Division of Materials Sciences and Engineering | |
| International Max Planck Research School for Chemistry and Physics of Quantum Materials |