Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 2: Superconductivity: Fe-based Superconductors - 1111, LiFeAs & As-free Pnictides

TT 2.11: Talk

Monday, March 26, 2012, 12:15–12:30, H 2053

Ferromagnetic resonance in Li_1−δFe_1−xNi_xAs single crystals — •A. Alfonsov, V. Kataev, C. Nacke, S. Aswartham, L. Harnagea, S. Wurmehl, A. U. B. Wolter, and B. Büchner — IFW Dresden, D-01169 Dresden, Germany

The magnetization measurements on Li_1−δFe_1−xNi_xAs samples reveal a spontaneous magnetization below a critical temperature T_c ∼ 140−160 K. In the electron spin resonance spectra measured at the X-band (9.5 GHz) frequency a strong ferromagnetic resonance (FMR) signal appears below T_c. Its behavior is similar in all samples. The temperature dependence of the resonance position of this signal corresponds to that of the spontaneous magnetization. The angular dependence of the position and of the linewidth of the signal, measured at low temperatures, suggests that the ferromagnetic magnetization is aligned in the FeAs plane. We discuss the properties of FMR signals in Li_1−δFe_1−xNi_xAs samples.