Abstract
Magnetism of the rhombohedral structure , a member of the geometric frustration series where the magnetic ions form a deformed pyrochlore lattice, was studied using dc and ac susceptibilities, heat-capacity, neutron powder-diffraction, and muon spin relaxation measurements. Antiferromagnetic transition was observed at with a much larger Curie-Weiss temperature of approximately , suggesting that is a geometrically frustrated magnet. Neutron-diffraction studies revealed the transition into a long-range antiferromagnetic order below with the spins on the triangular lattice planes disordered, and the other ones on the kagome lattice planes having frozen moments of less than 70% of the full moment. Spin fluctuations below were verified further using studies. The magnetically phase-separated feature and the spin fluctuation coexisting with a long-range magnetic order are considered to be of great interest for studying geometric frustration and the behavior of spin systems on prochlore and kagome lattices.
3 More- Received 3 April 2010
DOI:https://doi.org/10.1103/PhysRevB.82.024425
©2010 American Physical Society