Co-appearance of superconductivity and ferromagnetism in a Ca${}_2$RuO${}_4$ nanofilm crystal

Abstract

By tuning the physical and chemical pressures of layered perovskite materials we can realize the quantum states of both superconductors and insulators. By reducing the thickness of a layered crystal to a nanometer level, a nanofilm crystal can provide novel quantum states that have not previously been found in bulk crystals. Here we report the realization of high-temperature superconductivity in Ca${}_2$RuO${}_4$ nanofilm single crystals. Ca${}_2$RuO${}_4$ thin film with the highest transition temperature $T_c$ (midpoint) of 64~K exhibits zero resistance in electric transport measurements. The superconducting critical current exhibited a logarithmic dependence on temperature and was enhanced by an external magnetic field. Magnetic measurements revealed a ferromagnetic transition at 180~K and diamagnetic magnetization due to superconductivity. Our results suggest the co-appearance of superconductivity and ferromagnetism in Ca${}_2$RuO${}_4$ nanofilm crystals. We also found that the induced bias current and the tuned film thickness caused a superconductor-insulator transition. The fabrication of micro-nanocrystals made of layered material enables us to discuss rich superconducting phenomena in ruthenates.

References in corpus (10)

• Non-Abelian Anyons and Topological Quantum Computation
• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• Strong Peak in $T_c$ of Sr${}_2$RuO${}_4$ Under Uniaxial Pressure
• Tuning competing orders in La2-xSrxCuO4 cuprate superconductors by the application of an external magnetic field
• Universal self-field critical current for thin-film superconductors
• Giant superconducting fluctuations in the compensated semimetal FeSe at the BCS-BEC crossover
• Hallmarks of Hund's coupling in the Mott insulator Ca${}_2$RuO${}_4$
• Two-stage magnetic-field-tuned superconductor-insulator transition in underdoped La${}_{2-x}$Sr${}_x$CuO${}_4$
• Current-induced giant diamagnetism in the Mott insulator Ca2RuO4
• Tailoring the electronic properties of Ca${}_2$RuO${}_4$ via epitaxial strain

Cited by in corpus (9)

• Spin-orbit-entangled electronic phases in 4$d$ and 5$d$ transition-metal compounds
• Resistive transition of hydrogen-rich superconductors
• Altermagnetism in Two Dimensional Ca${}_2$RuO${}_4$ Perovskite
• Magnetic reorientation transition in a three orbital model for $\mathrm{C}{\mathrm{a}}_2\mathrm{Ru}{\mathrm{O}}_4$ -- Interplay of spin-orbit coupling, tetragonal distortion, and Coulomb interactions
• Sr${}_2$RuO${}_4$, like doped cuprates and barium bismuthate, is a negative charge-transfer gap even parity superconductor with $\frac{3}{4}$-filled oxygen band
• $d$-wave superconductivity as a model for diborides apart MgB${}_2$
• Vortex state in a superconducting mesoscopic irregular octagon
• Role of orbital off-diagonal spin and charge condensates in a three orbital model for $\mathrm{C}{\mathrm{a}}_2\mathrm{Ru}{\mathrm{O}}_4$ -- Coulomb renormalized spin-orbit coupling, orbital moment, and tunable magnetic order
• Terahertz spectroscopy evidence of possible 40 K superconductivity in rhenium-doped strontium ruthenates