Synthesis, structure and magnetic properties of rare-earth REMgAl11O19 (RE = Pr, Nd) compounds with two-dimensional triangular lattice

We report the synthesis, crystal structure and magnetic properties of Rare-earth hexaaluminates REMgAl11O19 (RE = Pr, Nd) crystallized in a hexagonal structure with space group P63/mmc, where the magnetically coupled rare-earth ions form perfect two-dimensional triangular layers well separated along c-axis. The magnetic susceptibilities reveal the dominant antiferromagnetic (AFM) interactions and no magnetic ordering down to 2 K with Curie Weiss temperature (θCW) θCW = −6.4 K and θCW = -3.4 K for RE = Pr and Nd, respectively. Furthermore, the AFM interactions are robust against the nonmagnetic dilution by doping Lanthanum (La3+) ions. The analysis of X-band electron spin resonance (ESR) spectra also supports the existence of AFM interactions in these two compounds. Our studies reveal a promising platform to investigate novel magnetic ground states in two-dimensional triangular lattice. •We discover a 2D triangular lattice magnets REMgAl11O19 (RE = Pr, Nd).•The magnetic results reveal the existence of strong antiferrromagnetic coupling.•The antiferromagnetic coupling is robust against the nonmagnetic defects.