26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Internal and external field effects upon crystal field excitations in $REFeO_3$ (RE = $Nd^{3+}$, $Er^{3+}$, $Yb^{3+}$, $Pr^{3+}$, and $Ho^{3+}$)

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Poster AIP | Condensed Matter & Materials (CMM)

Description

We systematically investigated crystal-field (CF) excitations of Kramers ($Nd^{3+}$, $Er^{3+}$, $Yb^{3+}$) and non-Kramers ($Pr^{3+}$, $Ho^{3+}$) rare-earth ions in $REFeO_3$ using optimized CF simulations. Internal magnetic fields from the $Fe^{3+}$ and $RE^{3+}$ sublattices split the ground-state doublets of all Kramers ions, generating low-energy excitations around 1 meV. In non-Kramers systems, low-energy excitations arise only when the ground state forms an accidental pseudo-doublet, as observed for $Ho^{3+}$ in $HoFeO_3$; such pseudo-doublets exhibit field-induced splitting analogous to Kramers ions. In contrast, true singlet ground states, exemplified by $Pr^{3+}$, show no zero-field splitting. Strong anisotropies are found in both internal- and external-field responses of the CF excitations in these $REFeO_3$. These results provide a unified explanation for the anomalous Zeeman splitting of CF ground states in $REFeO_3$.