Organometallic complexes formed by transition metals clusters and benzene molecules have already been synthesized, and in selected cases display magnetic properties controlled by external magnetic fields. We have studied Ni$_n$Bz$_n$ complexes made of nickel atoms surrounded by benzene molecules and here we focus specifically on the magnetic molecule Ni$_{ 3}$Bz$_{ 3}$. By means of calculations including relativistic spin-orbit terms, we show that this molecule reveals a large magnetic anisotropy energy of approximately 8 meV, found with the easy axis perpendicular to the metal atoms plane. Note that the matching bare Ni$_{ 3}$ cluster have similar magnetic anisotropy, however the easy axis is in-plane. Covering with benzene molecules is thus switching the easy axis from in-plane for Ni$_3$ to out-of-plane for Ni$_{ 3}$Bz$_{ 3}$. The large out-of-plane magnetic anisotropy of Ni$_{ 3}$Bz$_{ 3}$ suggests that this molecule could indeed be used as part in the design of molecular magnetic memories.
Categories: cond-mat.mtrl-sci