Berlin 2018 – scientific programme
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MA: Fachverband Magnetismus
MA 34: Spintronics (joint session MA/TT)
MA 34.6: Talk
Wednesday, March 14, 2018, 16:15–16:30, EB 202
Dynamics of Mn Local Moments in Metallic and Semiconducting Pnictides — M. A. Surmach1, P. Y. Portnichenko1, Z. Deng2,3, C. Q. Lin2,4,5, J. K. Glasbrenner6, I. I. Mazin6, D. L. Sun7, Y. Liu7, C. T. Lin7, A. Ivanov8, J. T. Park9, J. A. Rodriguez-Rivera10,11, and •D. S. Inosov1 — 1TU Dresden, Germany — 2Inst. of Physics, Beijing — 3Center for High Pressure Sci. & Technol., Beijing — 4Univ. of Chinese Academy of Sciences, Beijing — 5Collab. Innov. Center of Quantum Matter, Beijing — 6Naval Research Lab., Washington, USA — 7MPI-FKF, Stuttgart, Germany — 8ILL, Grenoble, France — 9MLZ, Garching, Germany — 10Univ. of Maryland, USA — 11NIST Center for Neutron Research, USA
We have investigated the effects of Mn doping in two materials isostructural to 122-type iron-based superconductors by neutron spectroscopy. First, we discuss the excitation spectrum of Mn-substituted BaFe2As2, where local magnetic clusters pinned to the impurity sites lead to an emergence of (π,π) magnetic excitations. We discuss their 3D character and the origin of the spin gap. The 2nd class of materials derives from the isostructural semiconductor BaZn2As2, giving rise to a dilute magnetic semiconductor upon Mn substitution. Hole doping by K provides an opportunity to tune the carrier concentration and the amount of magnetic moments independently. The resulting compound, (Ba1−xKx)(Zn1−yMny)2As2, is a ferromagnet with the maximal Curie temperature of 230 K. It offers a versatility of chemically tailored properties, as the hole doping is decoupled from spin injection and occurs in a different crystallographic layer.