Pressure-induced resurgence of the superconducting transition in spinel MgTi2O4 thin films

Lifen Shi; Zhuang Ni; Jun Hou; Wei Hu; Qian Li; Pengtao Yang; Bosen Wang; Yoshiya Uwatoko; Xiaoli Dong; Kui Jin; Jianping Sun; Jinguang Cheng

doi:10.1103/blwl-l16s

Pressure-induced resurgence of the superconducting transition in spinel MgTi2O4 thin films

Lifen Shi, Zhuang Ni, Jun Hou, Wei Hu, Qian Li, Pengtao Yang, Bosen Wang, Yoshiya Uwatoko, Xiaoli Dong, Kui Jin, Jianping Sun, Jinguang Cheng

DOI 10.1103/blwl-l16s · Physical Review B

T1

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Abstract

MgTi2O4 is a spinel superconductor with an optimal Tc≈5 K recently discovered by employing superlattice engineering. Here, we study the pressure effect on the superconducting properties of MgTi2O4 thin films deposited on the (00l)-oriented MgAl2O4 substrate via measurements of resistance under various pressures up to 12 GPa. We find that the superconducting Tc(P) displays a nonmonotonic evolution, i.e., it first shows a gradual decrease and then exhibits an enhancement above Pc∼3 GPa, resulting in a V-shaped double dome with two maxima. In addition, our results reveal an interesting correlation between Tc and the normal-state resistance, which exhibits an opposite trend with respect to Tc(P). Moreover, the extracted μ0Hc2(0) that exceeds the Pauli limit and the obtained large Maki parameter α suggest that the dominant pair-breaking effect is a spin-paramagnetic channel in the measured pressure range. In this work, we not only demonstrate the potential to further raise Tc of the Ti-based spinel superconductors but also offer more insight into the rich physics related to the superconducting mechanism of this family.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
MgTi2O4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	5.6	Pressure unresolved	onset
MgTi2O4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	3	Pressure unresolved	zero_resistance
MgTi2O4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	4	2.3 GPa	onset
MgTi2O4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.5	2.3 GPa	zero_resistance
MgTi2O4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	5.1	6.2 GPa	onset
MgTi2O4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	2.5	6.2 GPa	zero_resistance
MgTi2O4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6.3	11.8 GPa	onset
TiO Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	2.8	Pressure not reported	unknown
TiO Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7.4	Pressure not reported	unknown
Ti2O3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8	Pressure not reported	unknown
Ti3O5 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7.1	Pressure not reported	unknown
LiTi2O4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	13.7	Pressure not reported	unknown