Spin dynamics in molecular ring nanomagnets: Significant effect of acoustic phonons and magnetic anisotropies
arXiv:cond-mat/0608438 · doi:10.1143/JPSJ.75.103701
Abstract
The nuclear spin-lattice relaxation rate 1/T_1_ is calculated for magnetic ring clusters by fully diagonalizing their microscopic spin Hamiltonians. Whether the nearest-neighbor exchange interaction J is ferromagnetic or antiferromagnetic, 1/T_1_ versus temperature T in ring nanomagnets may be peaked at around k_B_T=|J| provided the lifetime broadening of discrete energy levels is in proportion to T^3^. Experimental findings for ferromagnetic and antiferromagnetic Cu^II^ rings are reproduced with crucial contributions of magnetic anisotropies as well as acoustic phonons.
5 pages with 5 figures embedded, to be published in J. Phys. Soc. Jpn. 75, No. 10 (2006)
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