Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 55: Multiferroic Oxide Thin Films and Heterostructures I (joint session KFM/TT/MA)
TT 55.4: Vortrag
Mittwoch, 14. März 2018, 10:30–10:45, EMH 225
Nonlinear spin-lattice coupling in EuTiO3: novel two-dimensional magneto-optical device for light modulation — •Annette Bussmann-Holder1, Krystian Rolder2, and Jürgen Köhler1 — 1Max-Planck-Institute for Solid State Research, Heisenbergstr. 1, D-70569 Stuttgart, Germany — 22Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice, Poland
EuTiO3 is antiferromagnetic at low temperature, namely below TN=5.7K. In the high temperature paramagnetic phase the strongly nonlinear coupling between the lattice and the nominally silent Eu 4f7 spins induces magnetic correlations which become apparent in muon spin rotation experiments and more recently in birefringence measurements in an external magnetic field. It is shown here, that high quality films of insulating EuTiO3 deposited on a thin SrTiO3 substrate are versatile tools for light modulation. The operating temperature is close to room temperature and admits multiple device engineering. By using small magnetic fields birefringence of the samples can be switched off and on. Similarly, rotation of the sample in the field can modify its birefringence Δn. In addition, Δn can be increased by a factor of 4 in very modest fields with simultaneously enhancing the operating temperature by almost 100K. The results can be understood in terms of paramagnon phonon interaction where spin activity is achieved via the local spin-phonon double-well potential.