Structure and magnetic properties of La2/3Sr1/3MnO3/ CaMnO3 multilayers.

M. GRANADA; M. SIRENA; L.B.STEREN; A.G. LEYVA

Buenos Aires, Argentina

Workshop; At the Frontiers of Condensed Matter II; 2004

In this work, we present structural and magnetic characterization of trilayers composed of ferromagnetic and metallic electrodes and antiferromagnetic insulator barriers. Our samples alternate La2/3Sr1/3MnO3 with CaMnO3 layers. These compounds have similar lattice parameters, so we expect an excellent matching of the different layers along the structure. Ferromagnetic manganites such as La2/3Sr1/3MnO3, are optimal materials to use as electrodes in tunnel junctions due to their large spin polarization as well as their chemical stability in air. To get a first insight of this system, we fabricated multilayers of La2/3Sr1/3MnO3/CaMnO3 (LSMO/CMO) by sputtering, using (100)SrTiO3 and (100)Mgo substrates. X-ray diffraction patterns show that the structure is strongly textured in the (100) direction when grown on SrTiO3, regardless of which material is first deposited onto the substrate. A different result is found on the same system grown on MgO: when the bottom layer is CaMnO3, the structure grows in the (110) orientation while it grows in the (100) direction when the bottom layer is La2/3Sr1/3MnO3. These results allow us to select the crystal orientation of the multilayer by introducing a buffer layer of CMO or LSMO. The composition of the samples has been controlled by EDAX and the layers topography analysed by AFM. Magnetic coupling of the ferromagnetic layers across the antiferromagnetic spacer is being studied with magnetization and ferromagnetic resonance measurements.