ISSN:
1089-7550
Quelle:
AIP Digital Archive
Thema:
Physik
Notizen:
The thickness dependence of electrical transport and magnetization of ultrathin La0.7Sr0.3MnO3 films has been investigated using epitaxial La0.7Sr0.3MnO3(LSMO)/SrTiO3 multilayers prepared by pulsed laser deposition. Layer thicknesses range from 1.9 to 10 nm for both constituents. Microstructural characterization by x-ray diffraction and transmission electron microscopy has confirmed a well-defined superlattice structure, coherent growth, and fairly smooth interfaces of the samples. Magnetization measurements show a pronounced drop of the ferromagnetic Curie temperature below a LSMO thickness of d=3 nm, accompanied by a strong rise of the coercive field. The in-plane electrical transport changes from metallic (dρ/dT〉0) to insulating at d∼2.3 nm. Three different types of magnetoresistance (MR) have been observed for d〈3 nm. In the sequence of decreasing d, the first resembles the grain boundary MR of polycrystalline LSMO, the second is positive, and the third is associated with a magnetic field-induced insulator-to-metal transition. Magnetic and transport results are discussed in the framework of a mixed-phase state of ferromagnetic metallic and less magnetically ordered insulating clusters in the ultrathin LSMO films. © 2001 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.1362649
