Robust pinned magnetisation in AIrO iridates, the case of ErIrO and LuIrO flux-grown single crystals.

In addition to complex spin-ice and spin-liquid states of rare-earth pyrochlore oxides, AIrO iridates have been recently proposed to host a cooling-field-controllable antiferromagnetic domain structure of iridium moments. Reliable and profound studies of the magnetic domain structure, including domains' interfaces, have been frequently limited by insufficient sample quality or lack of single crystals. We report the magnetic properties of the for-the-first-time synthesised LuIrO and ErIrO single crystals; focussing on the robust ferromagnetic component of magnetisation present in the material with the antiferromagnetically ordered state of the all-in-all-out (AIAO) type. Anisotropy of the system, as well as the effects of magnetic (Er) or nonmagnetic (Lu) local environments on Ir moments, is studied. The size of the domains is calculated based on a simplified domain wall model. Results are discussed in the framework of AIAO and AOAI domains and interfaces on the geometrically frustrated lattice.