Successive phase transitions and extended spin-excitation continuum in the S=1/2 triangular-lattice antiferromagnet Ba3CoSb2O9

H D Zhou; Cenke Xu; A M Hallas; H J Silverstein; C R Wiebe; I Umegaki; J Q Yan; T P Murphy; J-H Park; Y Qiu; J R D Copley; J S Gardner; Y Takano

doi:10.1103/PhysRevLett.109.267206

Successive phase transitions and extended spin-excitation continuum in the S=1/2 triangular-lattice antiferromagnet Ba3CoSb2O9

Phys Rev Lett. 2012 Dec 28;109(26):267206. doi: 10.1103/PhysRevLett.109.267206. Epub 2012 Dec 26.

Authors

H D Zhou¹, Cenke Xu, A M Hallas, H J Silverstein, C R Wiebe, I Umegaki, J Q Yan, T P Murphy, J-H Park, Y Qiu, J R D Copley, J S Gardner, Y Takano

Affiliation

¹ Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200, USA. hzhou10@utk.edu

PMID: 23368612
DOI: 10.1103/PhysRevLett.109.267206

Abstract

Using magnetic, thermal, and neutron measurements on single-crystal samples, we show that Ba3CoSb2O9 is a spin-1/2 triangular-lattice antiferromagnet with the c axis as the magnetic easy axis and two magnetic phase transitions bracketing an intermediate up-up-down phase in magnetic field applied along the c axis. A pronounced extensive neutron-scattering continuum above spin-wave excitations, observed below T(N), implies that the system is in close proximity to one of two spin-liquid states that have been predicted for a 2D triangular lattice.