We report the crystal growth, by the Bridgeman-Stockbarger method, and the basic magnetic properties of a new cobalt-based pyrochlore, NaSrCo2F7. Single-crystal structure determination shows that Na and Sr are completely disordered on the non-magnetic large atom A sites, while magnetic Co2+ fully occupies the pyrochlore lattice B sites. NaSrCo2F7 displays strong antiferromagnetic interactions (), a large effective moment (), and no spin freezing until 3 K. Thus, NaSrCo2F7 is a geometrically frustrated antiferromagnet with a frustration index . Ac susceptibility, dc susceptibility, and heat capacity are utilized to characterize the spin freezing. We argue that NaSrCo2F7 and the related material NaCaCo2F7 are examples of frustrated pyrochlore antiferromagnets with weak bond disorder.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- frustrated magnetism
- spin glass