title: Variable range hopping conductivity and spin glass behavior in spin-ladder Ba0.6K0.4Fe2Se3 single crystals.
abstract: Ba0.6K0.4Fe2Se3 (BKFS) single crystals were investigated by means of measurements of powder x-ray diffraction, temperature-dependent resistivity, anisotropic dc magnetization, ac magnetic susceptibility and specific heat. The powder x-ray diffraction indicates staggered iron displacements along the ladders with short and long Fe-Fe bond lengths (2.64(2) and 2.91(2) Å) variation. The resistivity of BKFS exhibits variable range hopping behavior with ln(ρ) ~ T(-1/2) at low temperature. The magnetic susceptibility χ(T) exhibits a sharp cusp at around 20 K in a zero-field-cooled process. The frequency-dependent ac magnetic susceptibility reveals that the cusp feature is attributable to spin glass behavior. The anisotropic ac magnetic susceptibility indicates that BKFS is probably an anisotropic Heisenberg-like spin glass with its easy magnetization plane perpendicular to the chain direction. The specific heat also supports an insulating and spin glass ground state. Extended Curie-Weiss behavior above 40 K was observed with a reduced effective moment (μ(eff) = 1.66 μ(B)/Fe for H is perpendicular to b and μ(eff) = 1.82 μB/Fe for H is parallel to b) in BKFS, which is close to the spin-only magnetism with S=1/2.
authors: Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China.
authors: Jin-Ke
authors: JK
authors: Bao
authors: Chun-Mu
authors: CM
authors: Feng
authors: Yong-Kang
authors: YK
authors: Luo
authors: Hao
authors: H
authors: Jiang
authors: Yun-Lei
authors: YL
authors: Sun
authors: Wen-He
authors: WH
authors: Jiao
authors: Chen-Yi
authors: CY
authors: Shen
authors: Zhu-An
authors: ZA
authors: Xu
authors: Guang-Han
authors: GH
authors: Cao