Hall effect in strained La0.85Ba0.15MnO3 thin films
Abstract
Perovskite manganese oxide is one of the best candidates for the realization of room temperature spin electronic devices. However the TC of the well-known (La,Sr)MnO3 and (La,Ca)MnO3 are strongly suppressed with decreasing film thickness due to the lattice mismatch and so on. Contrary, we have discovered unique properties on the TC of the La1-xBaxMnO3 thin films with a tensile strain from substrate (Phy. Rev. B. 64, 224418). That is, the TC of La0.85Ba0.15MnO3 epitaxial thin film remarkably increases from 258 K for 729nm thick film to above room temperature (305 K) for 24 nm thick film. The enhancement TC has been interpreted in terms of the strain-induced modification of the eg electron orbital state. In detail, an elongation of the in-plane Mn-O distance due to the strain effect is favorable for stabilization of the in-plane dx2-y2 orbital compared with the out-of-plane d3z2-r2 orbital, resulting in an increase of dx2-y2 character in the occupied eg state, which would enhance the electron hopping and the double-exchange interaction. To ensure above speculation and also know the details of the electrical parameters, Hall measurement was performed in this study. The carrier densities of various thick films were found to be almost constant value ( 6 x 1020 cm-3) at 10 K, whereas Hall mobility drastically increased with enhancement TC, from 5 cm2/Vs for 729 nm thick film to 50 cm2/Vs for 24 nm thick film. The increase of Hall mobility is consistent with the above-mentioned interpretation for enhancement TC .
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARN33012K