Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 42: Posters Magnetism I
MA 42.50: Poster
Wednesday, March 18, 2020, 15:00–18:00, P3
Investigating the CMR Effect in Eu5In2Sb6 by Means of Nonlinear Transport and Fluctuation Spectroscopy Measurements — •Marvin Kopp1, Merlin Mitschek1, Priscila Rosa2, Lennart Fox1, and Jens Müller1 — 1Institute of Physics, Goethe-University Frankfurt, Frankfurt (Main), Germany — 2Los Alamos National Laboratory, USA
The structures of Zintl phases illustrate a diversity of clusters, chains and other polyanionic frameworks and show air- and moisture sensitivity due to their components. Recently, air-stable heavy element analogues of the Zintl phases were synthesized as promising candidates for thermoelectric materials [1]. One of these new rare earth analogues is the antiferromagnetic system Eu5In2Sb6, which is a narrow band gap semiconductor and shows a colossal magnetoresistance (CMR effect). At the Néel Temperature TN=15 K, a sharp drop of the resistivity occurs on lowering the temperature and a strong suppression of the resistivity with applied magnetic field is observed, with magnetoresistance ratios of − 99.9 % at 15 K and 9 T. In order to test formation and percolation of magnetic polarons as a possible mechanism to explain the large negative magnetoresistive effect we have measured the third harmonic voltage signal giving access to the nonlinear transport, which is found to be non-zero around TN. In addition we have performed fluctuation (noise) spectroscopy measurements showing a 1/f-type behaviour of the noise power spectral density over a wide temperature range superimposed by distinct two-level fluctuations around TN.
[1] J. Mater Chem. C, 2015, 3, 10518.