Dielectric relaxation of the quantum nanomagnet Mn-12 acetate

The temperature- and frequency-dependent dielectric relaxation in the quant um nanomagnet Mn-12 acetate and its partially and fully deuterated analogs has been investigated. The four distinct dielectric modes following an acti vated behavior have been identified in the temperature range from 300-2.8 K and frequency window of 20 Hz-1 MHz. Analysis of the dielectric data in pa rtially and fully deuterated Mn-12 acetate indicates that the three slowest modes can be ascribed to the motion of H2O while the fourth mode to that o f the CH3 groups. [S0163-1829(99)09817-3].