Projects Magnetic molecules and molecular magnets
Metal-organic clusters and single-molecular/single-ion magnets (SMM) are intrinsically nanoscale objects which provide magnetic functionality at smallest lengths scales. They are intriguing systems not only as isolated micro scale quantum magnetic systems which can be addressed by external magnetic fields but also as potential candidates for quantum storage applications. Simply, SMMs have single or several magnetic ions as a core of a molecule which is surrounded by ligands. Owing to the ligand molecules, the magnetic cores are well separated from each other and get a magnetically well isolated status. Magnetic anisotropy of the core, specifically axial anisotropy, plays a key role to raise an anisotropy barrier resulting in magnetic bistability between the magnetic ground states which can yield slow relaxation and hysteresis of the magnetization, which is one of the few macroscopic quantum effects accessible to experiment. In addition to potential application, SMM hence provide model systems to experimentally investigate magneto-structural correlations and to test and develop numerical methods to predict and further understand the quantum nature of matter. For applications in quantum technologies, e.g., as qubits or single-molecular data storage, relaxation of the spin states is still too fast, which is closely related to the above mentioned magneto-structural properties. In Heidelberg, we particularly address tailored synthesis of novel magnetic molecular systems, their investigation at high fields, high (THz) frequency and down to the Milli-Kelvin regime, as well as numerical predictions of structure-property relation, e.g., in the BMBF project SpinFun, the Max-Planck Schools Matter to Life and for Quantum Dynamics in Physics, Chemistry and Biology. There is also a strong link to molecular biology as metalloprotein function is often associated with the spin state of paramagnetic centers. For example, knowledge of the spin state of Fe(IV) in myoglobin is of outmost relevance to understanding function in these proteins.
