Dresden 2006 – wissenschaftliches Programm

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MA: Magnetismus

MA 24: Magnetic Thin Films III

MA 24.4: Vortrag

Donnerstag, 30. März 2006, 11:00–11:15, HSZ 03

Piezoelectrically induced strain effects in ferromagnetic manganite films — •C. Thiele¹, L. Schultz¹, A. A. Levin², and K. Dörr¹ — ¹IFW Dresden, PF 270116, 01171 Dresden — ²Institut für Strukturphysik, TU Dresden, 01062 Dresden

Ferromagnetic perovskite manganites like La_0.7Sr_0.3MnO₃ (LSMO) have been predicted to be extremely sensitive to distortions of the crystal lattice due to strong electron-phonon coupling [1]. This has been verified by experiments on biaxially strained films grown epitaxially on monocrystalline substrates with slightly mismatching lattice parameter. Active electric control of in-plane strain in thin films on a piezoelectric substrate is very promising, since it avoids additional effects of changing microstructure and would allow direct recording of strain dependent properties. Lee and Dale have earlier chosen BTO crystals for this purpose [2]. In this contribution, the effect of dynamically induced in-plane strain in epitaxial LSMO films on piezoelectric substrates Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (100) is analyzed [3]. In-plane lattice constants have been reversibly varied by up to 0.15 % by application of an electrical voltage to the substrate, leading to a strong impact on the resistive and magnetic behavior of the studied LSMO films. Resistance and Magnetization show strain-dependent hysteresis with an amplitude of several % at 300 K. T_C increases by several degrees due to release of in-plane tensile strain. This work is supported by DFG, FOR 520.

[1] A. J. Millis et al., JAP 83 (1998) 1588; A.J. Millis, Nature 392 (1998) 147. [2] M. K. Lee et al., APL 77 (2000) 3547; D. Dale et al., APL 82 (2003) 3725. [3] C. Thiele et al. (subm).