Evolution of Superconductivity with Sr-Deficiency in Antiperovskite Oxide Sr3−xSnO

• Published in: Scientific reports Vol. 9; no. 1; p. 1831
• Main Authors: Oudah, Mohamed, Hausmann, Jan Niklas, Kitao, Shinji, Ikeda, Atsutoshi, Yonezawa, Shingo, Seto, Makoto, Maeno, Yoshiteru
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12-02-2019; Nature Publishing Group
• Subjects: 639/766/119/1003; 639/766/119/2792/4128; Data processing; Electrons; Humanities and Social Sciences; Impurities; Mossbauer spectroscopy; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-38403-8

Bulk superconductivity was recently reported in the antiperovskite oxide Sr
3−
x
SnO, with a possibility of hosting topological superconductivity. We investigated the evolution of superconducting properties such as the transition temperature
T
c
and the size of the diamagnetic signal, as well as normal-state electronic and crystalline properties, with varying the nominal Sr deficiency
x
0
. Polycrystalline Sr
3−
x
SnO was obtained up to
x
0
 = 0:6 with a small amount of SrO impurities. The amount of impurities increases for
x
0
 > 0.6, suggesting phase instability for high deficiency. Mössbauer spectroscopy reveals an unusual Sn
4−
ionic state in both stoichiometric and deficient samples. By objectively analyzing superconducting diamagnetism data obtained from a large number of samples, we conclude that the optimal
x
0
lies in the range 0.5 < 
x
0
 < 0.6. In all superconducting samples, two superconducting phases appear concurrently that originate from Sr
3−
x
SnO but with varying intensities. These results clarify the Sr deficiency dependence of the normal and superconducting properties of the antiperovskite oxide Sr
3−
x
SnO will ignite future work on this class of materials.