We characterize an unusual magnetic phase in orthorhombic SrCuO2 using neutron scattering. SrCuO2 contains zigzag spin chains formed by pairs of linear S=1/2 chains (J=180 meV) coupled through a frustrated interaction (|J’| ≲ 0.1J). For T < Tc1=5.0(4) K, an elastic peak develops in a gapless spectrum indicating spin freezing on a time scale δ t > 210-10 s. While the frozen state has long range order along chains (ξc > 200c) and a substantial correlation length, ξa = 60(25)a perpendicular to zigzag planes, the correlation length is only ξb = 2.2(3)b in the direction of frustrated interactions. We argue that slow dynamics of stripelike cooperative magnetic defects yield this anisotropic frozen state.
ASJC Scopus subject areas
- Physics and Astronomy(all)