Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 75: Multiferroics II (jointly with DF, DS, KR, MA)

TT 75.4: Vortrag

Mittwoch, 18. März 2015, 16:00–16:15, EB 107

Massive magnetoelectric modulation of the magnetic anisotropy in an epitaxial La_0.7Sr_0.3MnO₃/PMN-PT heterostructure — •Martin Wahler¹, Sujit Das¹, Kathrin Dörr¹, and Georg Schmidt^1,2 — ¹Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale), Germany — ²Interdisziplinäres Zentrum für Materialwissenschaften, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale), Germany

We use ferromagnetic resonance (FMR) to investigate the strain induced change of the in-plane magnetic anisotropy of an epitaxial ferromagnetic oxide layer on a piezoelectric substrate. The samples consist of 20 nm thick La_0.7Sr_0.3MnO₃ layers on two different substrates, namely Pb(Mg_1/3Nb_2/3)_0.72Ti_0.28O₃ (PMN-PT) (001) and (110) single crystals. The two substrates induce either isotropic or anisotropic in-plane strain, respectively. For La_0.7Sr_0.3MnO₃ on (001) PMN-PT substrate, it has already been demonstrated by SQUID magnetometry that the Curie-temperature and saturation magnetization can be changed by applying an electric field normal to the sample plane [1]. Here we show that for the same substrate orientation there is a small but significant change in FMR resonance fields along the directions of the magnetic easy axes. For the (110) substrate, however, a massive shift of the resonance fields is observed, resulting in a change of the uniaxial anisotropy of more than 0.5 kOe for an applied electric field of 12 kV cm⁻¹. All measurements are carried out at a temperature of 120 K.
C. Thiele et al., Phys. Rev. B, 75 054408 (2007)