Speaker
Description
In geometrically-frustrated Ce-based pyrochlores, such as Ce$_2$Zr$_2$O$_7$, the effective S=1/2 of the Ce3+ crystal field ground state doublet is known to act both as a conventional dipole magnetic moment, and as an octupole. This constrains the form of its near-neighbour Hamiltonian, and allows for different ordered or quantum disordered ground states in this family of materials, where either the dipolar or octupolar nature of the S=1/2 degree of freedom dominates. I will describe recent experiments [1,2], mostly neutron scattering and heat capacity, which show how the nature of the Ce3+ ground state doublet can be revealed, and how a particular form of quantum spin liquid can be identified as the likely ground state in Ce$_2$Zr$_2$O$_7$.
