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MA: Fachverband Magnetismus

MA 35: Poster 2

MA 35.18: Poster

Donnerstag, 8. September 2022, 16:00–18:00, P4

Exploring transient ferromagnetism in La_0.9Sr_0.1MnO₃ thin films — •Karen P. Stroh, Tim Titze, Henrike Probst, Stefan Mathias, Daniel Steil, and Vasily Moshnyaga — I. Physikalisches Institut, Georg-August-Universität Göttingen

In perovskite manganites such as La_1−xSr_xMnO₃ (LSMO), complex phase diagrams with different magnetic, electric, and structural phases are obtained as a function of chemical doping. Whilst x=0.33 is referred to as optimal doping, underdoped LSMO with x∼ 0.1−0.15 is close to a PM-I/FM-M phase boundary for T>T_C [1] and thus a suitable candidate for photo-induced transitions. Ultrafast laser pulses may photoionize electrons from Mn³⁺ to Mn⁴⁺, establishing a double exchange interaction and a FM state, so that the compositional phase boundary might temporarily also be crossed via “optical” doping [2].

Underdoped LSMO/SrTiO₃(100) thin films were epitaxially grown by metalorganic aerosol deposition (MAD) and investigated by time-resolved magneto-optical Kerr effect (MOKE) and pump-probe reflectivity (PPR). Temperature-, fluence-, and magnetic field-dependent measurements have been performed on timescales from femtoseconds to nanoseconds using a pulsed fs laser setup. Our results indicate a possibility to optically drive a paramagnetic-insulating LSMO into a transient ferromagnetic state above T_C on a sub-ps timescale.

Financial support by the DFG via Project 399572199 and within the SFB 1073 (TP A02) is acknowledged.

[1] Hemberger et al., Physical Review B 66, 094410 (2002)

[2] Matsubara et al., Physical Review Letters 99(20), 207401 (2007)