Thickness effects on the magnetic and electrical transport properties of highly epitaxial LaBaCo2O5.5+δ thin films on MgO substrates

The transport properties of double perovskite LaBaCo2O5.5+delta thin films with different thicknesses were systemically studied. A thin (7 nm in thickness), disordered LaBaCo2O5.5+delta layer was formed at the interface between the film and substrate. The films had a typical semiconductor behavior with antiferromagnetic and ferromagnetic behavior coexisting at low temperature. Although the Curie temperature was independent of the film thickness, the coercive fields and magnetizations increase with increasing the film thickness. An ultra large magnetoresistance effect value of about 44% was obtained at 60 K for the film of 82 nm. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4734386]