Magnetic Endohedral Metallofullerenes with Floppy Interiors

Investigations on the electronic structure and magnetic properties of a free Gd$_{3}$N and Gd$_{3}$N@C$_{80}$ have been carried out using to examine the stability and the electronic and magnetic properties of the endohedral species. Using a synergistic approach combining Stern-Gerlach experiments in beams and first principles electronic structure studies, it is demonstrated that an isolated Gd$_{3}$N has a ground state spin moment of 23 $\mu $B followed by a non-collinear state of 17.2 $\mu $B only 88 meV above the ground state. The large moment is largely due to localized f-electrons. As a Gd$_{3}$N is embedded inside a C$_{80}$ cage, the localized f-electrons maintain the magnetic character while the hybridization between the s,d states of isolated Gd$_{3}$N and p-states of C$_{80}$ leads to a strongly bound motif with an interaction energy of 13.63 eV and a large HOMO-LUMO gap of 1.48 eV. Gd$_{3}$N@C$_{80}$ is further shown to possess two isomers corresponding to the location of the N atom on either side of the Gd$_{3}$ triangle with an appreciable electric dipole moment and a low barrier of 91 meV for transition between them offering potential for a fluctuating dipole.