Speaker
Description
The putative quantum spin liquid (QSL) state exhibited by YbMgGaO$_4$ is largely
ascribed to the quasi-2D triangular lattice which the magnetic Yb$^{3+}$ moments
decorate in concert with anisotropic exchange and disorder in neighbouring
disordered Mg$^{2+}$/Ga$^{3+}$ bilayers [1,2,3]. We present new inelastic neutron
scattering (INS) measurements on YbMgGaO$_4$ as well as its isostructural sister
compounds: ErMgGaO$_4$ and YbCoGaO$_4$. Each material was synthesized as a
phase-pure powder and INS measurements were performed on IN6-Sharp with E$_i$
= 3.1 meV at the Institut Laue-Langevin. We discuss the observed hallmarks of a
QSL in YbMgGaO$_4$ and contrast these with signatures of frozen spin correlations
in each of ErMgGaO$_4$ and YbCoGaO$_4$ in the INS measurements. The case of
YbCoGaO$_4$ is an interesting one as it displays the interplay between a QSL-like
state associated with the Yb$^{3+}$ magnetism, interleaved with a two-dimensional
spin glass state originating from the disordered Co$^{2+}$ magnetism.
[1] Paddison, J., Daum, M., Mourigal, M. et al. Nature Phys 13, 117–122 (2017)
[2] Li, Y., Adroja, D., Zhang, Q. et al. Phys. Rev. Lett. 118, 107202 (2017)
[3] Zhu, Z., Maksimov, P. A., Chernyshev, A. L. et al. Phys. Rev. Lett. 119,
157201 (2017)
