Magnetic Structure and Phase Separation in Epitaxial SrCoOx Thin Films
Abstract
Bulk SrCoOx separates into three distinct ferromagnetic phases as the oxygen content is increased from x = 2.75 to 3.0, corresponding to TC = 165 K (SrCoO2.75) , TC = 220 K (SrCoO2.88) , and TC = 280 K (SrCoO3.0) . Over this composition, the lattice evolves smoothly and remains a single crystallographic phase. Using pulsed laser deposition and electrochemical oxidation, we have prepared epitaxial films of SrCoOx of varying thickness and orientation on SiTiO3 substrates. While in polycrystalline samples intermediate oxygen concentrations show a two-phase magnetic behavior, 100nm thick (0 0 1) films remain single phase but still favor the same ferromagnetic transitions. Thicker, 150 nm (1 1 1) films also order at comparable TC's, but again show two-phase behavior during deoxidation. Resonant x-ray diffraction on these samples reveals both commensurate and incommensurate ordering dependent on the oxidation state. This implies a charge or orbital ordering which may be influenced by finite size effects.
The work is supported by the NSF through contract # DMR-0907197 (UConn) and DMR-0706610 (NIU). Research at the CLS is supported by NSERC, NRC, CIHR, Prov. of Sask., WD Canada, and U. Saskatchewan.- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2013
- Bibcode:
- 2013APS..MARA14003R