Speaker
Description
The perovskite rare-earth R nickelates, RNiO$_3$, are the prototypical example of a metal-insulator transition in a strongly correlated metal. The transition can be tuned by choice of R, but LaNiO$_3$ remains a metal. In superlattices (SLs) with interlayers of LaAlO$_3$, LaNiO$_3$ can be driven insulating and antiferromagnetic if they are thin enough [1]. We used $^8$Li $\beta$-NMR, to study LaNiO$_3$ as a single crystal, thin film, and in SLs with LaAlO$_3$ [2,3]. In the SLs, we are unable to isolate the signal from $^8$Li in the LaAlO$_3$ layers. To unravel this mystery, we compare spin-lattice relaxation and frequency comb measurements in a LaAlO$_3$/LaNiO$_3$ bilayer, and LaNiO$_3$ and LaAlO$_3$ crystals.
In a frequency comb, four frequencies simultaneously irradiate all four quadrupole satellites. The comb spectra of LaNiO$_3$ and LaAlO$_3$ are distinct, with the former having a single peak close to zero, while the latter has large quadrupolar splitting and a pattern consistent with its rhombohedral distortion. The comb of the bilayer shows features of both. Interestingly, we observe a significant signal from LaNiO$_3$, even at an implantation energy where we expect the $^8$Li to be mostly in LaAlO$_3$. The spin-lattice relaxation measurements in the bilayer show no evidence of a non-relaxing component.
- A. V. Boris et al., Science 332, 937 (2011)
- V. L. Karner et al., Phys. Rev. B 100, 165109 (2019)
- V. L. Karner et al., Phys. Rev. B. 104, 205114 (2021)
| vkarner@alumni.uwo.ca | |
| Funding Agency | NSERC |
| Supervisors Name | W. Andrew MacFarlane |
| Supervisors Email | wam@chem.ubc.ca |
| Did you request an Invitation Letter for a Visitors Visa Application | No |
