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Nanomagnets in carbon cages

Encapsulation of lanthanide atoms inside fullerenes stabilizes unconventional metallic clusters

Scientists at Leibniz Institute for Solid State and Materials Research Dresden (IFW) have synthesized air-stable single molecule magnets, featuring unique magnetic properties. This represents an important step towards the integration of nanomagnets in modern spin-information technology.

Molecular material with magnetic atoms in the structure can be used as nano-sized magnets for building up high-density information storage devices and for spintronic applications, such as spin valves. They can also behave as ‘qubits’ in quantum information technology. During the last decade, there was a dramatic improvement of lanthanide single molecule magnets. Embedding lanthanide ions into molecular environments leads to nanomagnets with magnetic bistability and slow relaxation of magnetization. However, the synthesis of functional single molecule magnets with air and thermal stability required for applications still remains a great challenge.

Now there is a promising new approach by researchers at the Leibniz Institute for Solid State and Materials Research Dresden (IFW). Encapsulation of lanthanide atoms inside carbon cages (fullerenes) allows the stabilization of unconventional metallic clusters. Of particular interest is the case of encapsulated lanthanide dimers (Ln2) featuring a single-electron bond that could not be realized in any other molecular lanthanide compound so far. In order to understand the principles underlying their magnetic behavior, an array of air-stable Ln2@C80(CH2Ph) molecules were synthesized and studied in detail. The unique bonding situation leads to strong ‘gluing’ of the lanthanide magnetic moments in all molecules. This is very beneficial for the molecular magnetism, especially in Tb2@C80(CH2Ph) exhibiting giant coercivity and the highest blocking temperature of magnetization among dinuclear lanthanide molecule magnets.

Original publication: F. Liu et al. Air-stable redox-active nanomagnets with lanthanide spins radical-bridged by a metal-metal bond, Nature Communications (2019), 10, 571.

Figure:  Molecular structure of Ln2@C80(CH2Ph)

Fullerene with Lanthanide atoms

Molecular structure of Ln2@C80(CH2Ph)