Electronic structure of the molecule-based magnet Mn[N(CN)(2)](2) from theory and experiment

Abstract

The electronic structure of the Mn-based dycyanamide molecular magnetic crystal has been investigated using theoretical density-functional-based methods and experimental spectra. All data are in accord with a small gap insulator with a lattice consisting of Mn+2(d(5)) ions that are antiferromagnetically coupled at low temperatures. Due to partial covalent bonding with neighboring atoms, the local moments of the Mn atoms are reduced by about 10% as compared to an isolated ion. Calculated exchange constants suggest a antiferromagnetic/ferromagnetic energy difference of 36 meV per unit cell. Inclusion of spin-orbit coupling allows for the determination of the magnetic anisotropy parameter and the preferred axis of magnetization. The results are in good agreement with previous experiments.