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TT: Fachverband Tiefe Temperaturen
TT 4: f-Electron Systems
TT 4.6: Talk
Monday, March 18, 2024, 11:00–11:15, H 3005
Nonlinear Transport and Fluctuation Spectroscopy in antiferromagnetic EuT2P2 at the CMR transition. — •Marvin Kopp1, Charu Garg1, Sarah Krebber1, Kristin Kliemt1, Cornelius Krellner1, Sudhaman Balguri2, Fazel Tafti2, and Jens Müller1 — 1Institute of Physics, Goethe-University Frankfurt, Frankfurt (Main), Germany — 2Departments of Physics, Boston College, USA
The colossal magnetoresistance (CMR) effect has been a focal point of extensive research for decades, owing to its pivotal role in the physics of correlated electron systems and its potential applications. Unlike typical CMR compounds characterized by mixed valence, double exchange in manganites, or structural Jahn-Teller distortion and ferromagnetic ordering, our focus lies on EuT2P2 (X=Cd, Zn), with both compounds exhibiting a strikingly large negative MR significantly preceding their antiferromagnetic ordering temperature. Initial reports suggest that strong magnetic fluctuations could be responsible for the drastic change of resistance in the magnetic field [1]. In this work, we aim to investigate these fluctuations using higher harmonic resistance and resistance fluctuation (noise) spectroscopy. Higher harmonic measurements are sensitive to the small changes in magneto-electric coupling caused by the postulated forming of magnetic clusters (polarons), often hidden in standard resistance measurements. The dynamics of these magnetic clusters is studied using resistance noise spectroscopy as a function of temperature and magnetic field which can reveal further microscopic characteristics.
[1] Adv. Mat. 33 (2021) 2005755.
Keywords: CMR; Antiferromagnet; nonlinear Transport; Flucutation Spectroscopy