Field-induced incommensurate Magnetic Structures of the Triangular-lattice Antiferromagnet (CD3ND3)2NaRuCl6

The prospect of merging the common paradigms of geometric frustration on a triangular lattice and bond anisotropies in the strong spin-orbit coupling limit holds tremendous promise in the ongoing hunt for exotic quantum materials. The recently discovered organic quantum antiferromagnet (CD3ND3)2NaRuCl6 poses a rare candidate system to realize such physics, displaying a triangular arrangement of Ru3+ ions adopting the spin-orbital entangled j = ½ state. Thermodynamics and preliminary neutron diffraction data suggest a highly frustrated ground state with residual magnetic order below 0.22 K and a complex phase diagram in applied fields, including three incommensurate phases. We propose to investigate the temperature-dependence and refine the magnetic structures in the IC states of (CD3ND3)2NaRuCl6 realized in axial fields by means of single-crystal neutron diffraction. With its large area detectors capable of tracking moving incommensurabilities and the low-temperature capabilities optimized for magnetic diffraction on single crystals, the ToF-Laue instrument WISH will be indispensible for this purpose.