Probing magnetic order and disorder in the one-dimensional molecular spin chains CuF2(pyz) and [Ln(hfac)3(boaDTDA)]n (Ln = Sm, La) using implanted muons

Abstract

We present the results of muon-spin relaxation (SR) measurements on antiferromagnetic and ferromagnetic spin chains. In antiferromagnetic CuF2(pyz) we identify a transition to long range magnetic order taking place at K, allowing us to estimate a ratio with the intrachain exchange of and the ratio of interchain to intrachain exchange coupling as . The ferromagnetic chain [Sm(hfac)3(boaDTDA)]n undergoes an ordering transition at K, seen via a broad freezing of dynamic fluctuations on the muon (microsecond) timescale and implying . The ordered radical moment continues to fluctuate on this timescale down to 0.3 K, while the Sm moments remain disordered. In contrast, the radical spins in [La(hfac)3(boaDTDA)]n remain magnetically disordered down to T = 0.1 K suggesting .