PC-8-3
Orientation dependence of structural and critical current properties in symmetric [010]-tilt grain boundaries of Fe(Se,Te)
09:45-10:00 30/11/2023
*K. Iida1,8, Y. Yamauchi2, T. Hatano2,8, J. Hänisch3, Z. Guo4,8, H. Gao5, S. Tokuta6,8, H. Shi7, S. Hata4,5,7,8, A. Yamamoto6,8, H. Ikuta2
1. College of Industrial Technology, Nihon University
2. Department of Materials Physics, Nagoya University
3. Karlsruhe Institute of Technology
4. Department of Advanced Materials Science and Engineering, Kyushu University
5. The Ultramicroscopy Research Center, Kyushu University
6. Department of Applied Physics, Tokyo University of Agriculture and Technology
7. Interdisciplinary Graduate School of Engineering Sciences, Kyushu University
8. JST CREST
Understanding the grain boundary characteristics is a prerequisite for fabricating superconducting bulks and wires with high performance. For Co-doped BaFe2As2[1], Fe(Se,Te)[2-3] and NdFeAs(O,F)[4], the misorientation angle dependence of the critical current density Jc has been investigated on [001]-tilt grain boundaries. However, no data for other types of grain boundaries have been reported. Here, we report on the structural and transport properties of Fe(Se,Te) grown on CeO2-buffered symmetric [010]-tilt roof-type SrTiO3 bicrystal substrates. Structural analyses by X-ray diffraction and transmission electron microscopy revealed that misorientation angle of Fe(Se,Te) was smaller whereas misorientation angle of CeO2 was larger than that of the substrate. The difference in misorientation angle between the CeO2 buffer layer and the substrate is getting larger with increasing misorientation angle. This phenomenon can be explained by the inclined epitaxy model [5-6]. For misorientation angle larger than 24º of the substrates, misorientation angle of Fe(Se,Te) was zero, whereas misorientation angle of CeO2 was continuously increasing. Electrical transport measurements confirmed no reduction of inter-grain Jc for misorientation angle, indicative of no weak links for supercurrent transport. The intra-grain Jc of the films grown on bicrystal substrates is lower than Jc of the film grown on an ordinary SrTiO3(001) substrate. This is because the former Jc includes both the in- and out-of-plane components.
[1] T. Katase et al., Nat. Commun. 2, 409 (2011).
[2] W. Si et al., Appl. Phys. Lett. 106, 032602 (2015).
[3] E. Sarnelli et al., IEEE Trans. Appl. Supercond. 27, 7400104 (2017).
[4] K. Iida et al., Supercond. Sci. Technol. 32, 074003 (2019).
[5] H. Nagai, J. Appl. Phys. 45, 3789 (1974).
[6] J. E. Ayers and S. K. Ghandhi, J. Crys. Growth 113, 430 (1991).
This work was supported by JST CREST Grant Number JPMJCR18J4. This work was also partly supported by the Advanced Characterization Platform of the Nanotechnology Platform Japan sponsored by the Ministry of Education Culture, Sports, Science and Technology (MEXT), Japan.
