Magnetic and electronic states in (LaMnO3)2(SrMnO3)2 superlattices fabricated on an (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 substrate, which exhibit a large nontrivial negative magnetoresistance (MR) effect, have been investigated. The crystal structure and the Mn valence state were determined using x-ray scattering measurements near the Mn K edge. These measurements revealed that the Mn valences in the LaMnO3 and SrMnO3 layers are 3+ and 4+, respectively; that is, valence modulation coincides with the La/Sr stacking structure. The Mn spin structure was studied by means of resonant soft x-ray scattering at the Mn L2,3 edge and neutron magnetic scattering measurements. We succeeded in detecting a magnetic signal indicating ferromagnetism at the interface. Finally, we suggest that the origin of the MR is the competition between ferromagnetism at the interface and underlying antiferromagnetism.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2015 Dec 7|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics