Uncertainty estimates for magnetic relaxation times and magnetic relaxation parameters

Abstract

Uncertainties in magnetic relaxation times from AC magnetometry are derived and a program for obtaining them is described, allowing statistically meaningful magnetic relaxation parameterisation.

A Study of Magnetic Relaxation in Dysprosium(III) Single‐Molecule Magnets

“…Compounds 1 – 11 show temperature (Figures S12–S22 in the Supporting Information) and frequency (Figures S23–S33 in the Supporting Information) dependence in alternating current (ac) susceptibilities under zero direct current (dc) field. To analyse the relaxation mechanisms, characteristic relaxation times, τ , were extracted from a simultaneous fit of χ′ and χ′′ by using the generalised Debye model with the CC‐FIT2 program, which derives ESDs in magnetic relaxation times from the underlying α parameters . The α parameters for the 12 compounds studied show a range of temperature dependencies (Tables S25–S36 and Figures S34–S44 in the Supporting Information).…”

“…We have used the α parameters to determine ESDs in the relaxation times following the approach of Reta and Chilton; these are shown in the plots of 1/ τ versus T (Figure and Figures S45–S52 in the Supporting Information). The data for compound 1 can be fitted by using Orbach+QTM or Raman + QTM expressions and give values of U eff =54±22 cm −1 , log [ τ 0 (s)]=−9.08±2.18 with log [ τ QTM (s)]=−2.75±0.15 (Figure a) or log [ C (s −1 K − n )]=−6.80±4.00, and n= 13.09±5.05 with log[ τ QTM (s)]=−2.79±0.15 (Figure S45 in the Supporting Information).…”

“… and because we have refitted the data by using the procedure in ref. . [e] Compound 2 a is a doped sample of 2 , with about 9% Dy as Y.…”

Strangely attractive: Collaboration and feedback in the field of molecular magnetism

“…A clear correlation between the size of the distributions and the quality of crystal structures was found, and the tool CC‐FIT2 to standardize data treatment was presented. [ 27 ]…”

“…The new generation of highly axial Dy(III) SMMs have brought enormous U eff values, and thus, design criteria must now shift toward considering the dynamic properties of molecules and crystals. To that end, predictive tools such as the one developed by the Chilton Group, as well as in other groups, [ 17,27,31,32 ] are necessary to drive the field forward.…”