SKM 2021 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 15: Posters Magnetism IV

MA 15.42: Poster

Donnerstag, 30. September 2021, 13:30–16:30, P

Coupling of magnetic and electric order in hybrid improper ferroelectric Ca₃Mn_1.9Ti_0.1O₇ — •Yannik Zemp¹, Mads C. Weber¹, Thomas Lottermoser¹, Morgan Trassin¹, Bin Gao², Sang-Wook Cheong², and Manfred Fiebig¹ — ¹Department of Materials, ETH Zurich — ²Rutgers University, New Jersey

Multiferroic hybrid improper ferroelectrics such as Ca₃Mn_1.9Ti_0.1O₇ (CMTO) provide a novel mechanism to couple ferroelectricity and ferromagnetism. Both ferroic orders are induced by the same structural distortions. Theoretically, these structural distortions allow an electrical control of the magnetic order. Experimental evidence of such a coupling is lacking, however, because high leakage currents prevent contact-based electrical measurements. Here we use two complementary non-contact methods, namely SQUID magnetometry and optical second harmonic generation (SHG) to scrutinize the magnetic and polar orders and their coupling in CMTO. We find clear evidence for a ferromagnetic moment below T_N = 115 K. Furthermore, we detect a massive increase in the SHG signal below the magnetic ordering temperature. Using SHG spectroscopy and domain analysis, we unveil the origin of this increase as a direct influence of the magnetic order on the ferroelectric state. This work shows that the magnetic and polar orders in multiferroic hybrid improper ferroelectrics can indeed be strongly coupled.