Orthorhombic-to-tetragonal transition of SrRuO3 layers in Pr0.7Ca0.3MnO3/SrRuO3 superlattices

M Ziese (1) , I Vrejoiu (2) , E Pippel (2) , A Hähnel (2) , E Nikulina (1, 2, 3) , D Hesse (1, 2)

1 Faculty of Physics and Geosciences
2 Max Planck Institute of Microstructure Physics
3 CIC NanoGUNE

High-quality Pr 0.7 Ca 0.3 MnO 3 /SrRuO 3 superlattices with ultrathin layers were fabricated by pulsed laser deposition on SrTiO 3 substrates. The superlattices were studied by atomically resolved scanning transmission electron microscopy, high-resolution transmission electron microscopy, resistivity and magnetoresistance measurements. The superlattices grew coherently without growth defects. Viewed along the growth direction, SrRuO 3 and Pr 0.7 Ca 0.3 MnO 3 layers were terminated by RuO 2 and MnO 2, respectively, which imposes a unique structure to their interfaces. Superlattices with a constant thickness of the SrRuO 3 layers, but varying thickness of the Pr 0.7 Ca 0.3 MnO 3 layers showed a change of crystalline symmetry of the SrRuO 3 layers. At a low Pr 0.7 Ca 0.3 MnO 3 layer thickness of 1.5 nm transmission electron microscopy proved the SrRuO 3 layers to be orthorhombic, whereas these were non-orthorhombic for a Pr 0.7 Ca 0.3 MnO 3 layer thickness of 4.0 nm. Angular magnetoresistance measurements showed orthorhombic (with small monoclinic distortion) symmetry in the first case and tetragonal symmetry of the SrRuO 3 layers in the second case. Mechanisms driving this orthorhombic to tetragonal transition are briefly discussed.

Mots clés: 75.70.Cn; 75.47.-m; 75.47.Lx; 75.30.Gw; 68.37.-d

M Ziese, I Vrejoiu, E Pippel, A Hähnel, E Nikulina, et al.. Orthorhombic-to-tetragonal transition of SrRuO3 layers in Pr0.7Ca0.3MnO3/SrRuO3 superlattices. Journal of Physics D: Applied Physics, 2011, 44 (34), pp.345001. ⟨10.1088/0022-3727/44/34/345001⟩. ⟨hal-00646920⟩