Single Molecule Magnet for Quantum Information Process'

Abstract

In this chapter, we review recent studies of single molecule magnets (SMMs) for application in electronic devices using the spin degree of freedom. In such devices, SMMs are combined with metal electrodes, which makes the characterization of the molecules on surfaces mandatory. In the first section, we examine recent developments in the synthesis and magnetic characterization of lanthanide double-decker SMMs. By tuning the ligand and crystal packing, it is found that Ln–Ln interaction can be changed and consequently the magnetic relaxation slowed down. Second, we see examples in which SMMs are applied for electronic devices using the spin properties of SMMs. Spintronic devices are fabricated combining TbPc 2 derivative molecule and single-walled carbon nanotube (SWCNT). SWCNT works as a quantum dot and the SMMs adsorbed on SWCNT as second quantum dots. The device demonstrates a current change due to the spin flip of the SMMs. The experiments executed in the mK region can read out the information of the nucleus spin state of SMMs. Third, we review recent scanning tunneling microscope (STM) characterization of the SMM film deposited on metal surfaces. STM is a powerful technique not only for the topographic observation of the SMM molecules and their film formation but also for the characterization of electronic and spin states of SMMs on surfaces. The spin state of the SMM can be examined by observing the Kondo effect, which is a many-body effect caused by the shielding of an isolated spin by conduction electron. We examine how the spin state of SMMs changes with an adsorption of surfaces, with a formation of molecule–molecule interaction, and with a variation of ligands.