Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.37: Poster
Dienstag, 28. März 2006, 15:15–19:15, P1
Exploring lattice effects on transport properties in manganite/alumina superlattices — •Yuansu Luo and Konrad Samwer — I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen
Superlattice properties of out-of-plane lattice spacing d modulation and interfacial dilatation were used to explore lattice effects, i.e. changes in Mn-O-Mn bond length of MnO6 octahedra, on transport behaviors in manganite/alumina multilayers. Epitaxial growth and high quality of stacking as well structural coherency (length ξ > bilayer period Λ) were confirmed by x-ray measurements. As the measure of lattice distortion, the average d, coherency length ξ, Curie temperature TC, magnetization M, coercive field Hc as well as resistance R are found to be a function of the interface fraction 1/Λ. Accordingly, we divided each manganite layer into two parts, i.e. weakly distorted No-dqinnermostNo-dq atomic layers and strongly dilated interfacial atomic layers, as is well clarified by observation of two component magnetization loops and huge variation in R values of current in- and perpendicular to- plane (CIP & CPP). At low T, the CPP value provides a magnetotunneling effect, but near TC of the interfacial atomic layers, the low-bias tunneling current is oscillated with applied magnetic field, which may be associated with field-induced changes in density of eg electron state near the Fermi level.
Supported by DFG-project, SA 337/9-1