Magnetization induced resistance switching effects in YBa
2Cu
3O
7- La
1-xSr
xMnO
3heterostructures
M. van Zalk*, M. Veldhorst, A. Brinkman, J. Aarts, H. Hilgenkamp
*Faculty of Science and Technology and Mesa+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
We have fabricated bi- and trilayers composed of the high-temperature superconductor YBa2Cu3O7 (YBCO) and the half-metallic ferromagnet La1-xSrxMnO3 (LSMO).
Heterostructures are pulsed laser deposited on SrTiO3 (001) as well as on SrTiO3 (305). On the latter, tilted epitaxial growth partly yields ab-plane contact between YBCO and LSMO. As a result of the uniaxial magnetic anisotropy in the (305)-oriented structures, we observe sharp magnetization switching behavior. At temperatures close to the superconducting transition temperature (Tc), we find resistance jumps induced by magnetization switching, resulting in a magnetization dependence of Tc. The results are similar to what is commonly being interpreted as the (inverse) spin switch effect. For the bilayers, we find that the switching effect can also be observed, provided that the
ferromagnetic layer is grown with considerable roughness. Our results indicate that the switching behavior arises from magnetic stray fields from the ferromagnetic layers that penetrate into the superconductor.
Figure 1 (a) Trilayer structure grown on SrTiO3 (305). Indicated are the YBCO crystal directions.
(b) Magnetization loop of the trilayer. The
dashed lines denote the coercive fields of the top and bottom layer. (c) Resistance of the middle YBCO layer in the superconducting transition as a function of magnetic field.
(a) (b)
(c)
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