A new family of single-molecule magnets: structural and magnetic characterization of self-assembled monolayers

Time period: 2012-07-01 to 2015-06-30

Project leader: Rasmus Westerström

Funder: Swedish Research Council

Type of award: Project grant

Total fundning: 3 150 000 SEK

The aim of the proposed project is to study the magnetism of a new family of singlemolecule magnets (SMMs), and determine how their magnetic properties are modified when interacting with the surface of different substrates. Single-molecule magnets exhibit a slow relaxation of the magnetization, resulting in hysteresis effects similar to those observed in bulk magnets but of pure molecular origin. This could be explored in future molecular electronics where each spin can be used as a "bit" of information for highdensity storage and quantum computing. Because of the difficulties of adsorbing SMMs onto surfaces, their interaction with different substrates is unexplored. I will use a new type of SMM which can be deposited and characterized under ultra-high vacuum. By using synchrotron radiation at low temperatures, in particular x-ray magnetic circular dichroism (XMCD), I will determine whether the intrinsic magnetic properties are retained upon adsorption. The structure and a local bonding geometry of the molecular surface layer will be determined by low temperature scanning tunneling microscopy and x-ray photoelectron diffraction. The molecules consist of a tri-metal nitrogen cluster inside a C80 cage. Which combination of metal ions exhibits the longest spin relaxation times will be addressed. In addition to XMCD, the molecular magnetism will be studied using a magnetometer equipped with a superconducting quantum interference device (SQUID).