Low-energy spin dynamics in rare-earth perovskite oxides
Abstract We review recent studies of spin dynamics in rare-earth orthorhombic perovskite oxides of the type RMO 3 , where R is a rare-earth ion and M is a transition-metal ion, using single-crystal inelastic neutron scattering (INS). After a short introduction to the magnetic INS technique in genera...
Saved in:
Published in | Journal of physics. Condensed matter Vol. 33; no. 40; pp. 403001 - 403027 |
---|---|
Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
United States
IOP Publishing
06.10.2021
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Abstract
We review recent studies of spin dynamics in rare-earth orthorhombic perovskite oxides of the type RMO
3
, where R is a rare-earth ion and M is a transition-metal ion, using single-crystal inelastic neutron scattering (INS). After a short introduction to the magnetic INS technique in general, the results of INS experiments on both transition-metal and rare-earth subsystems for four selected compounds (YbFeO
3
, TmFeO
3
, YFeO
3
, YbAlO
3
) are presented. We show that the spectrum of magnetic excitations consists of two types of collective modes that are well separated in energy: gapped magnons with a typical bandwidth of <70 meV, associated with the antiferromagnetically (AFM) ordered transition-metal subsystem, and AFM fluctuations of <5 meV within the rare-earth subsystem, with no hybridization of those modes. We discuss the high-energy conventional magnon excitations of the 3
d
subsystem only briefly, and focus in more detail on the spectacular dynamics of the rare-earth sublattice in these materials. We observe that the nature of the ground state and the low-energy excitation strongly depends on the identity of the rare-earth ion. In the case of non-Kramers ions, the low-symmetry crystal field completely eliminates the degeneracy of the multiplet state, creating a rich magnetic field-temperature phase diagram. In the case of Kramers ions, the resulting ground state is at least a doublet, which can be viewed as an effective quantum spin-1/2. Equally important is the fact that in Yb-based materials the nearest-neighbor exchange interaction dominates in one direction, despite the three-dimensional nature of the orthoperovskite crystal structure. The observation of a fractional spinon continuum and quantum criticality in YbAlO
3
demonstrates that Kramers rare-earth based magnets can provide realizations of various aspects of quantum low-dimensional physics. |
---|---|
Bibliography: | JPCM-118593.R1 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-3 content type line 23 ObjectType-Review-1 USDOE Office of Science (SC), Basic Energy Sciences (BES) AC05-00OR22725 |
ISSN: | 0953-8984 1361-648X |
DOI: | 10.1088/1361-648X/ac1367 |