Low energy magnetic excitations in triangular-lattice compound PrMgAl11O19

Searching for new compounds free from impurity and/or structure disorder is essential for realizing the quantum spin liquid (QSL) state. We have identified a new rare-earth-based triangular-lattice compound PrZnAl11O19 as a good QSL candidate with a perfect triangular structure and no magnetic ordering down to 0.05 K based on powder measurements. Having centimeter-sized single crystals now using the optical floating zone technique, we propose to study the detailed low-energy magnetic excitations in its analog PrMgAl11O19. Whether or not the appearance of the excitation continuum due to the spinon will be essential to answer if the compound is in the QSL state. For this purpose, we ask for 3 days beamtime on the LET spectrometer equipped with a heliox that could cool down to 300 mK.