Magnetic order and charge separation in 2D distorted triangular lattice systems [formula omitted

Abstract

Magnetic properties of organic compounds with two-dimensional distorted triangular lattice structure, β ′ - X [ Pd ( dmit ) 2 ] 2 are investigated by the muon spin relaxation ( μ SR ) method, where X is counter cation. We have previously reported that the X = Me 4 P salt ( 1, Me = CH 3 ) shows a very sharp antiferromagnetic (AFM) transition at 39.3 K. We have carried out μ SR measurements on other two Pd ( dmit ) 2 salts: the X = Et 2 Me 2 P salt ( 2, Et = C 2 H 5 ) and the Et 2 Me 2 Sb salt ( 3). In compound 2, an AFM transition at lower T N = 15 K with a smaller enhancement of the muon spin relaxation is observed, indicating a larger effect of the spin frustration than in 1. The zero-field μ SR time spectra of 3 showed an enhancement of the relaxation below ∼ 80 K , but did not show precessions. Recently, it has been suggested that this salt undergoes a phase transition to a charge-separated nonmagentic state. It is expected that the enhancement of the relaxation is related to the spin localization attributable to the charge separation.