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TT: Tiefe Temperaturen

TT 13: Correlated Electrons: Metal Insulator Transition - Part 1

TT 13.3: Talk

Tuesday, March 28, 2006, 12:15–12:30, HSZ 105

Disorder effects in manganites: Griffiths phase regime in La_1−xSr_xMnO₃ — •J. Deisenhofer¹, D. Braak², H.-A. Krug von Nidda¹, J. Hemberger¹, R.M. Eremina³, V.A. Ivanshin⁴, A.M. Balbashov⁵, G. Jug⁶, A. Loidl¹, T. Kimura⁷, and Y. Tokura⁷ — ¹EP V, Center for Electronic Correlation and Magnetism, University of Augsburg, Germany — ²TP II, Institute for Physics, University of Augsburg, Germany — ³E.K. Zavoisky Physical-Technical Institute, Kazan, Russia — ⁴Kazan State University, Kazan, Russia — ⁵Moscow Power Engineering Institute, Moscow, Russia — ⁶Dipartimento di Fisica e Matematica, Universita’ dell’Insubria, Como, Italy — ⁷Department of Applied Physics, University of Tokyo, Japan

By means of electron spin resonance and magnetic susceptibility measurements a novel triangular phase regime has been discoverd in the system La_1−xSr_xMnO₃. This phase is characterized by the coexistence of ferromagnetic entities within the globally paramagnetic phase far above the magnetic ordering temperature. The nature of this phase can be understood in terms of Griffiths singularities arising due to the presence of correlated quenched disorder in the orthorhombic phase.