FRUSTRATED MAGNETISM IN A KAGOMÉ STAIRCASE LATTICE

Joel S. Helton and Jeffrey W. Lynn

NIST Center for Neutron Research

Co₃V₂O₈ displays S=3/2 moments arrayed geometrically frustrated kagomé staircase lattice.  The geometric frustration of the antiferromagnetic kagomé lattice is partially lifted by further-neighbor interactions.  This combination of geometric frustration and competing interactions yields a complex phase diagram: an incommensurate antiferromagnetic order that arises below T = 11.3 K evolves and displays two commensurate lock-in phases before entering the ferromagnetic ground state below T = 6.2 K.  Neutron diffraction experiments with small magnetic fields applied parallel to the easy axis yield a new, distinct commensurate antiferromagnetic phase with a propagation vector of (0 0.4 0).  Critical scattering near the incommensurate-to-paramagnetic phase transition is also explored.