Synthesis, disorder and Ising anisotropy in a new spin liquid candidate PrMgAl11O19

Abstract

Here we report the successful synthesis of large single crystals of triangular frustrated PrMgAl _11 O _19 using the optical floating zone technique. Single crystal x-ray diffraction (XRD) measurements unveiled the presence of quenched disorder within the mirror plane, specifically ~7% of Pr ions deviating from the ideal 2 d site towards the 6 h site. Magnetic susceptibility measurements revealed an Ising anisotropy with the c -axis being the easy axis. Despite a large spin–spin interaction that develops below ~10 K and considerable site disorder, the spins do not order or freeze down to at least 50 mK. The availability of large single crystals offers a distinct opportunity to investigate the exotic magnetic state on a triangular lattice with an easy axis out of the plane.

Keywords

• spin liquid
• disorder
• frustration
• triangular lattice
• Ising anisotropy