Some new trends in the design of single molecule magnets

• Published in: Pure and applied chemistry Vol. 89; no. 8; pp. 1119 - 1143
• Main Authors: Aldoshin, Sergey M., Korchagin, Denis V., Palii, Andrew V., Tsukerblat, Boris S.
• Format: Journal Article
• Language: English
• Published: Berlin De Gruyter 01.08.2017; Walter de Gruyter GmbH
• Subjects: Angular momentum; Anisotropy; blocking temperature; Coupling (molecular); Crystal structure; Magnetic anisotropy; magnetic properties; Magnetization reversal; magnetization reversal barrier; magnetochemistry; Magnets; Mendeleev XX; Metal ions; orbitally-dependent superexchange; Rare earth elements; rational design; relaxation of magnetization; single ion magnets; single molecule magnets; Spin-orbit interactions; transition metals; Trends; unquenched orbital angular momentum
• ISSN: 0033-4545; 1365-3075
• DOI: 10.1515/pac-2017-0103

In this review we briefly discuss some new trends in the design of single molecule magnets based on transition (3d, 4d, 5d) and rare-earth (4f) metal ions. Within this broad theme the emphasis of the present review is placed on the molecules which exhibit strong magnetic anisotropy originating from the unquenched orbital angular momenta in the ground orbitally degenerate (or quasi-degenerate) states. Along with the general concepts we consider selected examples of the systems comprising orbitally-degenerate metal ions and demonstrate how one can benefit from strong single-ion anisotropy arising from the first-order orbital angular momentum. The role of crystal fields, spin-orbit coupling and structural factors is discussed. Some observation stemming from the analysis of the isotropic exchange interactions, magnetic anisotropy and strongly anisotropic orbitally-dependent superexchange are summarized as guiding rules for the controlled design of single molecule magnets exhibiting high barriers for magnetization reversal and, consequently, high blocking temperatures.