Publication Date:
2017-04-14
Description:
Author(s): K. A. Ross, J. M. Brown, R. J. Cava, J. W. Krizan, S. E. Nagler, J. A. Rodriguez-Rivera, and M. B. Stone Quantum effects in magnetic materials are prevalent when the magnetic ions support spin-½ moments, as in Cu 2 + -based materials. Strong quantum effects can also be achieved when the large angular momentum states are reduced to an effective spin-½ subspace ( S eff =½) by the combined effect of spin-orbit coupling and the crystal electric field. A consequence of this is the introduction of anisotropy to the g tensor and the effective exchange interactions. Such anisotropic S eff =½ models have recently been applied successfully to rare-earth based frustrated pyrochlore materials, where they are found to lead to particularly rich phenomenology for XY-like g tensors. Here, it is shown that a similar quantum model should apply to the recently discovered “high temperature” Co 2 + pyrochlores, NaCaCo 2 F 7 and NaSrCo 2 F 7 , based on a fit to their single ion levels as measured via inelastic neutron scattering. The effect of the intrinsic crystalline disorder on the anisotropy of the S eff =½ moments in these materials is also estimated. [Phys. Rev. B 95, 144414] Published Thu Apr 13, 2017
Keywords:
Magnetism
Print ISSN:
1098-0121
Electronic ISSN:
1095-3795
Topics:
Physics
Permalink
