Static and dynamic magnetic response of fragmented haldane-like spin chains in layered Li3Cu2SbO6

Abstract

The structure and the magnetic properties of layered Li3Cu2SbO6 are investigated by powder X-ray diffraction, static susceptibility, and electron spin resonance studies up to 330 GHz. The XRD data experimentally verify the space group C2=m with halved unit cell volume in contrast to previously reported C2=c. In addition, the data show significant Li=Cuintersite exchange. Static magnetic susceptibility and ESR measurements show two magnetic contributions, i.e., quasifree spins at low-temperature and a spin-gapped magnetic subsystem, with about half of the spins being associated to each subsystem. The data suggest ferromagnetic-antiferromagnetic alternating chains with JFM = -285 K and JAFM = 160 K with a significant amount of Li-defects in the chains. The results are discussed in the scenario of fragmented 1D S = 1 AFM chains with a rather high defect concentration of about 17% and associated S =1=2 edge states of the resulting finite Haldane chains. © 2016 The Physical Society of Japan.