Determination of a zero-field splitting parameter D in Mn 12Ac below 20 K

Abstract

Molecular magnet Mn 12Ac has a large molecular spin S=10. The uniaxial crystalline anisotropy splits the energy levels in zero magnetic field into 10 doublets and one singlet. The simplest Hamiltonian in magnetic field H z for this symmetry is H=−DS z 2−gμ B μ 0HS z . The zero-field splitting parameter D has been determined from measured M( H) in weak magnetic field at different temperatures. The approximate value is D=0.7 K .