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Ferromagnetic Interactions in Highly Stable, Partially Reduced TiO 2 : The S= 2 State in Anatase
Author(s) -
Chiesa Mario,
Livraghi Stefano,
Giamello Elio,
Albanese Elisa,
Pacchioni Gianfranco
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201610973
Subject(s) - anatase , ferromagnetism , electron paramagnetic resonance , hydrothermal circulation , materials science , spins , spectroscopy , spin states , spin (aerodynamics) , ion , condensed matter physics , tetrahedron , range (aeronautics) , crystallography , chemical physics , chemistry , nuclear magnetic resonance , physics , chemical engineering , thermodynamics , photocatalysis , biochemistry , organic chemistry , quantum mechanics , engineering , catalysis , composite material
We report direct evidence for quintuplet spin states in a particular kind of reduced TiO 2 anatase obtained by the mild oxidation of TiB 2 under hydrothermal conditions. Continuous‐wave and pulse EPR spectroscopy at X and Q band frequencies provide compelling evidence for the presence of S = 2 states, stable in a wide range of temperatures up to room temperature. A tentative model, corroborated by spin‐polarized DFT calculations, is proposed, which consists of four ferromagnetically interacting Ti 3+ ions with distances ranging from 0.5 nm to 0.8 nm and tetrahedral arrangement.