Flux pinning mechanisms and a vortex phase diagram of tin-based inverse opals

Abstract

Three-dimensional periodic tin structures were synthesized by filling pores in silicon opals with a sphere diameter of 194 nm (Sn190) and 310 nm (Sn300). The samples were examined by the ultra-small-angle x-ray diffraction method, energy dispersive x-ray microanalysis and scanning electron microscopy. It was found that the inverse opal structure consists of tin nanoparticles inscribed in octahedral and tetrahedral pores with diameters of 128 nm and 70 nm for the sample Sn300, and 80 nm and 42 nm for the sample Sn190. The study of the magnetic properties of the samples by SQUID magnetometry showed that magnetization reversal curves exhibit hysteretic behavior. The mechanisms of magnetic flux pinning in the samples depend on the size of the tin nanoparticles. Tin nanoparticles in Sn300 behave like a classical type-I superconductor. The hysteretic behavior of the magnetization reversal curves at low magnetic fields is due to the formation of a network of superconducting contours in Sn300. These superconducting contours effectively trap the magnetic flux. The octahedral tin nanoparticles in Sn190 remain type-I superconductors, but smaller tetrahedral particles behave like type-II superconductors. Type-I and II superconducting particles in Sn190 lead to the coexistence of different mechanisms of flux pinning. These are flux trapping by superconducting contours at low magnetic fields and flux pinning by tetrahedral particles due to the surface barrier at high magnetic fields.

Superconducting Quantum Metamaterials from High Pressure Melt Infiltration of Metals into Block Copolymer Double Gyroid Derived Ceramic Templates

“…This is corroborated by work performed on inverse opal templated metals, where evidence suggests vortex pinning commensurate with the opal lattice size. [ 37,38 ] However, in contrast to the inverse opal type structures, which consist of large nodes connected by an order of magnitude smaller in diameter “weak links”, the gyroid structures present in this work consist of networked struts of relatively homogeneous diameter throughout. This distinction is important for consideration of the origin of flux pinning as well other properties which arise due to confinement, as explored in the next section.…”

Analog of the intertype superconductivity in nanostructured materials

“…As scanning electron microscopy and small-angle synchrotron scattering revealed, the sizes of octahedral and tetrahedral particles equal 128 and 70 nm for S1 and 80 and 42 nm for S2. The detailed structural and magnetic results will be published in other work [19]. A schematic view of the realized inverted opal structures is shown on…”

The Promise of Soft‐Matter‐Enabled Quantum Materials

“…Adapted with permission. [ 71 ] Copyright 2019, IOP Publishing Ltd. d) MoGe nanowires from DNA templates. Adapted with permission.…”

“…An alternative route, the most common so far to 3D mesoscale periodic architectures in superconductors, is via infiltration into self-assembled bulk colloidal crystals. This strategy has been employed to create inverse opal structured lead, [119][120][121] tin, [71,121,122] indium, [121,123] gallium, [121,124] bismuth, [125] lead/bismuth alloys, [121] and tungsten bronzes. [126] In the cases of classical type-I metals, the inverse opal or opal composite materials behave similarly to granular superconductors, with sizedependent changes in magnetization behavior and typically increased critical fields and temperatures.…”

“…Copyright 2001, Elsevier Science Ltd. c) Tin inverse opal via melt injection of opal lattice; inset: depiction of the lattice geometry. Adapted with permission [71]. Copyright 2019, IOP Publishing Ltd. d) MoGe nanowires from DNA templates.…”