Evidence of field induced slow magnetic relaxation in cis-[Co(hfac)2(H2O)2] exhibiting tri-axial anisotropy with a negative axial component. Issue 23 (2nd June 2017)

• Record Type: Journal Article
• Authors: Korchagin, Denis V.; Palii, Andrew V.; Yureva, Elena A.; Akimov, Alexander V.; Misochko, Eugenii Ya.; Shilov, Gennady V.; Talantsev, Artem D.; Morgunov, Roman B.; Shakin, Alexander A.; Aldoshin, Sergey M.; Tsukerblat, Boris S.
• Is Part Of: Dalton transactions. Volume 46:Issue 23(2017)
• Page Start: 7540
• Page End: 7548
• Publication Date: 2017-06-02
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c7dt01236e
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : We report a combined experimental characterization and theoretical modeling of the hexa-coordinated high-spin Co(ii ) complex cis -[Co(hfac)2 (H2 O)2 ] (I ). Abstract : We report a combined experimental characterization and theoretical modeling of the hexa-coordinated high-spin Co(ii ) complex cis -[Co(hfac)2 (H2 O)2 ] (I ). The magnetic static field (DC) data and EPR spectra (measurements were carried out on the powder samples of diluted samples cis -[Co0.02 Zn0.98 (hfac)2 (H2 O)2 ]) were analyzed with the aid of the parametric Griffith Hamiltonian for the high-spin Co(ii ) supported by the ab initio calculations of the crystal field (CF) parameters, g -factors and superexchange parameters between H-bonded Co(ii ) ions in the neighboring molecules in a 1D network. This analysis suggests the presence of the easy axis of magnetic anisotropy and also shows the existence of a significant rhombic component. The detected frequency dependent (AC) susceptibility signal shows that complexI exhibits slow paramagnetic relaxation in the applied DC field belonging thus to the class of non-uniaxial field induced single ion magnets with a negative axial component of anisotropy. It is demonstrated that the main contributions to the relaxation come from the direct one-phonon process dominating at low temperatures, while the contribution of the two-phonon Raman process becomes important with increasing temperature.