Местоположение издательства:UNIVERSITETSKAYA NAB., 7/9, ST. PETERSBURG,RUSSIA, 199034
Первая страница:669
Последняя страница:669
Аннотация:Single molecule and single ion magnets (SMMs and SIMs, respectively) are atomic scale objects that show slow magnetization relaxation at low temperatures. Most modern SIMs are represented by metalorganic complexes of transition element ions and lanthanide ions with low coordination numbers providing strong axial anisotropy. Such molecular complexes are often unstable, so transition metal ions may be introduced into positions with crystal field anisotropy in crystal structure of inorganic solid forming magnetic centers with bistable ground states (inorganic SIMs or ISIMs).High-spin Fe3+ free ion possesses a half-filled 3d-level without orbital momentum in its ground state. However slow relaxation of magnetization was observed in several compounds of iron(III) exhibiting low Ueff. In addition, the reduced electron-phonon interaction of such electronic configuration may provide a longer spin coherence time required to create qubits for quantum computers.In the present work imbedding of iron in an inorganic solid and possibility of forming the first Fe3+ based ISIM are considered. Mayenite Ca12Al14O33 was chosen as a crystalline host. It represents an anti-zeolite structure with positively charged cages partially filled with oxygen-based anions. Al atoms are found in two types of distorted tetrahedra of oxygen atoms (Al1 and Al2). Fe3+ can partially substitute Al3+ at the trigonally distorted tetrahedral site Al1 keeping its high-spin configuration. Such distortion may provide a crystal field anisotropy required to form a SIM unit.
