Abstract
The intriguing thermophysical properties of have been subject to investigation for more than 20 years. In particular, an exotic ground state, phase IV, emerges under doping with La. We report resonant x-ray scattering results on the order parameter symmetries in phase IV of , which condenses below . The results reveal a degree of mesoscopic dipole antiferromagnetic order, with propagation vector , both below and above . Below , this polarization coexists with long-range antiferro-octupole (AFO) order also at . The marked differences in temperature dependence and spatial correlation suggest a state of order parameter segregation at low temperature. A simple model of AFO order, consistent with the polarization dependent azimuth symmetries, the Bragg angle, and temperature dependence is given.
- Received 24 April 2005
DOI:https://doi.org/10.1103/PhysRevLett.95.117206
©2005 American Physical Society