Low temperature magnetic properties and spin dynamics in single crystals of Cr8Zn antiferromagnetic molecular rings

A detailed experimental investigation of the e?ects giving rise to the magnetic energy level structure in the vicinity of the level crossing (LC) at low temperature is reported for the open antiferromagnetic molecular ring Cr8Zn. The study is conducted by means of thermodynamic techniques (torque magnetometry, magnetization and specific heat measurements) and microscopic techniques (nuclear magnetic resonance line width, nuclear spin lattice, and spin-spin relaxation measurements). The experimental results are shown to be in excellent agreement with theoretical calculations based on a minimal spin model Hamiltonian, which includes a Dzyaloshinskii-Moriya interaction. The first ground state level crossing at ?0Hc1 = 2.15 T is found to be an almost true LC while the second LC at ?0Hc2 = 6.95 T has an anti-crossing gap of