Muon spin relaxation study of the Haldane state formed in ferromagnetic–antiferromagnetic alternating Heisenberg chains (CH3)2CHNH3CuCl3

Abstract We report on zero-field (ZF) and longitudinal-field (LF) dependence of μ + SR time spectra at 2.0, 12 and 50 K in (CH 3 ) 2 CHNH 3 CuCl 3 , which consists of ferromagnetic–antiferromagnetic alternating Heisenberg chains with S= 1 2 . As a result, the ZF-μ + SR time spectra showed that the relaxation rate which was due to electron spins slightly increased with decreasing temperature. Furthermore, from the analysis of the LF-μ + SR time spectra, the fluctuation of the local field which was due to electron spins appeared at 2.0 K but it disappeared at 12 and 50 K .