Single-Molecule Nanomagnets

Abstract

Single-molecule magnets straddle the classical and quantum mechanical worlds, displaying many fascinating phenomena. They may have important technological applications in information storage and quantum computation. We review the physical properties of two prototypical molecular nanomagnets, Mn12-acetate and Fe8: Each behaves as a rigid, spin-10 object and exhibits tunneling between up and down directions. As temperature is lowered, the spin-reversal process evolves from thermal activation to pure quantum tunneling. At low temperatures, magnetic avalanches occur in which the magnetization of an entire sample rapidly reverses. We discuss the important role that symmetry-breaking fields play in driving tunneling and in producing Berry-phase interference. Recent experimental advances indicate that quantum coherence can be maintained on timescales sufficient to allow a meaningful number of quantum computing operations to be performed. Efforts are under way to create monolayers and to address and manipulate individual molecules.

Limit cycles and chaos in the current through a quantum dot

“…[26] and [28]. This possibility is also closely related to transport through single molecular magnets [29][30][31][32] , for which our large spin would map to a magnetic atom and the isolated levels of our quantum dot to molecular orbitals.…”

Trigonal Bipyramid Ni3Cl3O2 Cluster Showing the High-Spin S = 3 Ground State with Uniaxial Magnetic Anisotropy

“…Preparation of [Ni 3 (tmen) 3 Cl 3 (¯3-OMe)(¯3-OH)](BPh 4 )¢ 0.5MeOH¢0.5CH 2 Cl 2 (1). To a green solution of NiCl 2 ¢ 6H 2 O (0.487 g, 2.1 mmol) in MeOH (6 mL) was added N,N,N¤,N¤-tetramethylethylenediamine (tmen) (0.32 mL, 2.2 mmol) and NaBPh 4 (0.240 g, 0.7 mmol).…”

“…In the present work, we utilized ligands as simplified as possible and have actually prepared a novel triangle compound [Ni 3 (tmen) 3 (¯2-Cl) 3 (¯3-OMe)(¯3-OH)](BPh 4 )¢0.5MeOH¢ 0.5CH 2 Cl 2 (1; tmen: N,N,N¤,N¤-tetramethylethylenediamine or tmeda) having an approximate D 3h symmetry for the complex cation moiety (Scheme 1). In this regard, there have been a few reports on triangular nickel(II) compounds having a threefold symmetry.…”

“…In this regard, there have been a few reports on triangular nickel(II) compounds having a threefold symmetry. Two known compounds [Ni 3 (tmen) 3 X 4 (OH)]X (X = Cl (2), Br (3)) 14,15 with symmetrical belt bridges also seem to be attractive. Their synthesis and structures have already been reported, but no magnetic properties were known.…”

Nanoelectronics «bottom – up»: thermodynamics of electric conductor, information-driven battery and quantum entropy

“…Последние 10 лет научных и технологиче-ских исследований вселяют надежду на создание компьютеров со спиновой структурой хранения и передачи информации. Надежды связывают с моле-кулярными магнитами [27,28].…”