caa a22 4500 605545367 CHVBK 20210128100935.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s00723-015-0661-8 doi (NATIONALLICENCE)springer-10.1007/s00723-015-0661-8 High-Field ESR Measurements of the Spin-Gap System in Polarized Microwaves [Elektronische Daten] [S. Kimura, K. Watanabe, T. Kashiwagi, H. Yamaguchi, M. Hagiwara, Z. Honda] We have performed high-field electron spin resonance (ESR) measurements of the isolated antiferromagnetic dimer system Na2Co2(C2O4)3(H2O)2 by illuminating circularly polarized microwaves at 162GHz. Different from a usual ESR signal by the magnetic dipole transition, the resonance signal, coming from the direct transition between the singlet and triplet states in this compound, is suggested to show absence of circular dichroism. From this curious behavior, we consider that the direct transition in Na2Co2(C2O4)3(H2O)2 is driven by oscillating electric fields of microwaves. We propose that the spin current mechanism is responsible to induce a finite probability for the electric-dipole-active transition between the singlet and the triplet states in Na2Co2(C2O4)3(H2O)2. Springer-Verlag Wien, 2015 Kimura S. Institute for Materials Research, Tohoku University, 980-8577, Sendai, Japan aut Watanabe K. Institute for Materials Research, Tohoku University, 980-8577, Sendai, Japan aut Kashiwagi T. Graduate School of Pure and Applied Sciences, University of Tsukuba, 305-8573, Tsukuba, Japan aut Yamaguchi H. College of Integrated Arts and Science, Osaka Prefecture University, 588-8531, Sakai, Japan aut Hagiwara M. Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, 560-0043, Osaka, Japan aut Honda Z. Graduate School of Science and Engineering, Saitama University, 338-8570, Saitama, Japan aut Applied Magnetic Resonance Springer Vienna 46/9(2015-09-01), 1035-1039 0937-9347 46:9<1035 2015 46 723 https://doi.org/10.1007/s00723-015-0661-8 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00723-015-0661-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kimura S. Institute for Materials Research, Tohoku University, 980-8577, Sendai, Japan aut NATIONALLICENCE 700 1- Watanabe K. Institute for Materials Research, Tohoku University, 980-8577, Sendai, Japan aut NATIONALLICENCE 700 1- Kashiwagi T. Graduate School of Pure and Applied Sciences, University of Tsukuba, 305-8573, Tsukuba, Japan aut NATIONALLICENCE 700 1- Yamaguchi H. College of Integrated Arts and Science, Osaka Prefecture University, 588-8531, Sakai, Japan aut NATIONALLICENCE 700 1- Hagiwara M. Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, 560-0043, Osaka, Japan aut NATIONALLICENCE 700 1- Honda Z. Graduate School of Science and Engineering, Saitama University, 338-8570, Saitama, Japan aut NATIONALLICENCE 773 0- Applied Magnetic Resonance Springer Vienna 46/9(2015-09-01), 1035-1039 0937-9347 46:9<1035 2015 46 723