Surface-phase superconductivity in Mg-deficient V-doped MgTi${}_2$O${}_4$ spinel

Abstract

Around fifty years ago, LiTi${}_2$O${}_4$ was reported to be first spinel oxide to exhibit a superconducting transition with highest T${}_c$ $\approx$ 13.7 K. Recently, MgTi${}_2$O${}_4$ has been found to be the only other spinel oxide to reveal a superconducting transition with a T${}_c$ $\approx$ 3 K, however, its superconducting state is realized only in thin film superlattices involving SrTiO${}_3$. We find that a V-doped Mg${}_{1-x}$Ti${}_2$O${}_4$ phase, which gets stabilized as a thin surface layer on top of stoichiometric and insulating V-doped MgTi${}_2$O${}_4$ bulk sample, exhibits high-temperature superconductivity with T${}_c$ $\approx$ 16 K. The superconducting transition is also confirmed through a concomitant sharp diamagnetic transition immediately below T${}_c$. The spinel phase of the superconducting surface layer is elucidated through grazing-incidence X-ray diffraction and Micro-Raman spectroscopy. A small shift of the sharp superconducting transition temperature ($\sim$ 4 K) with application of a high magnetic field (upto 9 Tesla) suggests a very high critical field for the system, $\sim$ 25 Tesla. Thus, V-doped Mg${}_{1-x}$Ti${}_2$O${}_4$ exhibits the highest T${}_c$ among spinel superconductors and also possesses a very high critical field.

arXiv comment5 pages, 4 figures

References in corpus (18)

• Upper critical fields and thermally-activated transport of Nd(O_0.7F_0.3)FeAs single crystal
• Orbitally-driven Peierls state in spinels
• Spin singlet formation in MgTi${}_2$O${}_4$: evidence of a helical dimerization pattern
• The Ginzburg-Landau Theory of Type II superconductors in magnetic field
• Weak-link behavior of grain boundaries in superconducting Ba(Fe1-xCox)2As2 bicrystals
• To use or not to use cool superconductors?
• Anomalous magnetoresistance in the spinel superconductor LiTi2O4
• Valence bond crystal in a pyrochlore antiferromagnet with orbital degeneracy
• Magnetic field dependence of low temperature specific heat of spinel oxide superconductor LiTi_2O_4
• Scanning tunneling spectroscopy of superconductivity on surfaces of LiTi2O4(111) thin films
• Orbital-spin order and the origin of structural distortion in MgTi${}_2$O${}_4$
• The $c$-axis dimer and its electronic break-up: the insulator-to-metal transition in Ti${}_2$O${}_3$
• Superconductivity in the Cu(Ir1-xPtx)2Se4 Spinel
• Emergent superconductivity in single crystalline ${\mathrm{MgTi}}_2{\mathrm{O}}_4$ films via structural engineering
• Anomalies of upper critical field in the spinel superconductor LiTi${}_2$O${}_{4-\delta }$
• Superconductivity with the enhanced upper critical field in the Pt-Doping CuRh2Se4 spinel
• Possible routes to superconductivity in the surface layers of V-doped Mg${}_{1-\delta }$Ti${}_2$O${}_4$ through multiple charge transfers and suppression of Jahn-Teller activity
• Epitaxial stabilization of an orthorhombic Mg-Ti-O superconductor

Cited by in corpus (1)

• Exploring the Electronic Nature of Spinel Oxides: A Review of Their Electron Interactions and Prospects