Stabilization of Short- and Long-Range Magnetic Orderingthrough the Cooperative Effect of 1D [CuO4] Chainsand [CuO2X2] Quadrilateral in Quasi-1D Spin-1/2 Systems.

Abstract

Quasi-1D chain antiferromagnetswith reduced structural dimensionality area rich playground for investigating novel quantum phenomena. We report the synthesis, crystal structure, and magnetism of two novel quasi-1D antiferromagnets, β-PbCu2(TeO3)2Cl2 (I) and PbCu2(TeO3)2Br2 (II).Their magnetic frameworks are constructed via Cu-based quasi-1D [Cu(2)O4]zigzagchains with square-planar [Cu(1)O2X2] (X = Cl or Br) separated among 1D chains. Specific heat measurements show l peaks at ~9 K and ~19 Kfor I and II, respectively. Moreover, both broad maximums (χmax = 90 K for I and 80 K for II) and small kinks (TN ≈ 9 K for I and 19 K for II) have been observed in magnetic susceptibility measurements of I and II. Bonner-Fisher model fitting, and theoretical analyses were performed to evaluate the magnetic exchange interactions. Our experimental and theoretical results and structure-properties relationship analysis reveal the coexistence of short-and long-range magnetic ordering from the cooperative effect of 1D [CuO4]chains and [CuO2X2] quadrilateral.