Electron spin resonance study of the photo-induced phase transition in the spin-crossover complex

• Published in: Journal of luminescence Vol. 94; pp. 529 - 532
• Main Authors: Shirai, Masanobu, Yonemura, Naoki, Tayagaki, Takeshi, Kan’no, Ken-ichi, Tanaka, Koichiro
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2001; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron paramagnetic resonance and relaxation; Electron spin resonance; Exact sciences and technology; Iron group (3d) ions and impurities (ti-cu); Magnetic resonances and relaxations in condensed matter, mössbauer effect; Photo-induced phase transition; Physics; Structural change; Photo-induced phase transition; 64.90.+b; 76.30.Fc; 78.90.+t; Electron spin resonance; Structural change; Crystal field splitting; Phase transformations; ESR; Photoinduced effect; Crystal field; Experimental study; Pyridine derivatives; g-factor; Iron complexes; Impurities; Spin crossover; Chloro complex; Cobalt additions
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/S0022-2313(01)00388-X

The photo-induced phase transition (PIPT) in the spin-crossover complex, [Fe II(2-pic) 3]Cl 2EtOH, has been investigated by monitoring the ESR signals of impurity Co 2+ ions. The principal values of the g-tensor of Co 2+ ions in the low temperature phase at 4 K were determined as g xx =2.1, g yy =2.6 and g zz =7.1. The light irradiation resonant to the d–d transition of Fe 2+ ions (532 nm) causes the change of g zz from 7.1 to 7.35. The intensity of the photo-induced signal exhibits nonlinear dependence on the irradiation time. These results suggest that the crystal field on a Co 2+ ion would approach to that of cubic symmetry by PIPT.