Origin of the relaxation barriers in a family of MReIV(CN)2 single-chain magnets (M = MnII, NiII, and CoII): a theoretical investigation. (3rd November 2014) - Zhang, Yi-Quan
Abstract : Theoretical exploration of the Δ ξ and Δ A in terms of D, J, and S in three MRe IV (CN)2 single-chain magnets. Abstract : Through investigation of the origin of the relaxation barriers and the magneto-structural correlations in three (DMF)4 MRe IV Cl4 (CN)2 (DMF = dimethylformamide; M = Mn II (1 ), Ni II (2 ), and Co II (3 )) single-chain magnets (SCMs) in the intermediate regime between the Ising and the Heisenberg limits using hybrid functional theory (B3LYP) and complete active space second-order perturbation theory (CASPT2) methods, we succeeded in obtaining the magnetic anisotropy and correlation energy barriers Δ A and Δ ξ in terms of D (magnetic anisotropy parameter), J (magnetic exchange coupling constant), and S (spin value). B3LYP calculations show that the antiferromagnetic Re IV –Mn II coupling interactions decrease with the increase of the Mn–N–C angle, while the ferromagnetic Re IV –Ni II coupling interactions increase with the increase of the Ni–N–C angle. But, the Re IV –Co II exchange interactions with the variation of the Co–N–C angle are almost the same. The total energy barriers Δ τ of1 and2 mainly come from the contribution of the transverse anisotropy of Re IV, while the Mn II and Ni II ions only transmit the exchange coupling between Re IV and almost have no contributions. For3, however, both of the Re IV and Co II ions have contributions to the total energy barrier.