On the Magnetic Excitation Spectra of Ba(Fe^sub 0.9^Co^sub 0.1^)^sub 2^As^sub 2^ in the Superconducting State

• Published in: Journal of the Physical Society of Japan 2011-01, Vol.80, p.1
• Main Authors: Sato, M, Tatematsu, S, Yasui, Y, Kobayashi, Y, Moyoshi, T, Motoya, K, Kakurai, K
• Format: Article
• Language: English
• Subjects: Magnetism; Orbits; Spectrum analysis; Superconductivity; Superconductors; Symmetry; Temperature
• ISSN: 0031-9015; 1347-4073

Magnetic excitation spectra of Ba(Fe ... Co ... ) ... As ... obtained for aligned crystals with the superconducting transition temperature T ... ~23 K are presented after an overview of results of our preceding studies on the symmetry of the order parameter ... Although many researchers have reported that their experimental results are consistently explained by the so-called S ... symmetry, and believe that the spin-fluctuation is relevant to the superconducting mechanism of Fe pnictide superconductors. However, the situation is not so simple, because almost all these data can be understood by the S ++ -symmetry, too. Furthermore, as we first pointed out and discussed in detail, the rates of the T ... suppression by nonmagnetic impurities can hardly be explained by the S ± symmetry. Here, we show our own data of the magnetic excitation spectra of Ba(Fe ... Co ... ) ... As ... , and discuss which one of the S ± and S ++ -symmetries can better describe the characteristics of the peak observed there. These processes are important, because the S ± and S ++ symmetries are connected with the spin-fluctuation mechanism and a newly proposed one related to the orbital degrees of freedom of the systems, respectively. (ProQuest: ... denotes formulae/symbols omitted.)