TY - JOUR
T1 - Superconducting property and Fe valence state of FeSe thick films grown from high temperature solution
AU - Qi, Xiaoding
AU - Wang, Jiun Yi
AU - Kuo, Jui Chao
AU - Yates, Karen A.
AU - Cohen, Lesley F.
N1 - Funding Information:
This work was partially supported by the National Science Council of Taiwan under the grant number: NSC-96-2628-E-006-010-MY3 and by the National Cheng Kung University via Landmark Projects.
PY - 2011/6/2
Y1 - 2011/6/2
N2 - Thick FeSe films (1-2 μm) were grown from high temperature solution with SeSn as the flux. Electron backscatter diffraction confirmed the films of tetragonal β phase with high crystallinity. Superconducting transition was observed by magnetic measurements, with the onset Tc of 6.1 K for the as-grown films and rising to 6.9 K after post-growth annealing at 400 °C, which was still 1.5 K lower than the sintered powder samples. X-ray photoelectron spectroscopy showed that the Fe 2p3/2 binding energy in the FeSe compound was composed of two peaks at 707.8 eV and 706.6 eV, respectively. The former was close to the value of Fe in polarized ionic bonds, while the later had the typical value in metallic bondings. The ratio of the two bondings was 1.56 and 1.94 for the films and sintered powders, respectively. The critical temperature may have some correlation with the ratio of the two bondings. A lower average Fe valence was probably the cause for the lower T c observed in thick films.
AB - Thick FeSe films (1-2 μm) were grown from high temperature solution with SeSn as the flux. Electron backscatter diffraction confirmed the films of tetragonal β phase with high crystallinity. Superconducting transition was observed by magnetic measurements, with the onset Tc of 6.1 K for the as-grown films and rising to 6.9 K after post-growth annealing at 400 °C, which was still 1.5 K lower than the sintered powder samples. X-ray photoelectron spectroscopy showed that the Fe 2p3/2 binding energy in the FeSe compound was composed of two peaks at 707.8 eV and 706.6 eV, respectively. The former was close to the value of Fe in polarized ionic bonds, while the later had the typical value in metallic bondings. The ratio of the two bondings was 1.56 and 1.94 for the films and sintered powders, respectively. The critical temperature may have some correlation with the ratio of the two bondings. A lower average Fe valence was probably the cause for the lower T c observed in thick films.
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U2 - 10.1016/j.jallcom.2011.03.054
DO - 10.1016/j.jallcom.2011.03.054
M3 - Article
AN - SCOPUS:79955587280
SN - 0925-8388
VL - 509
SP - 6350
EP - 6353
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - 22
ER -