Paramagnetic Meissner effect in ZrB₁₂single crystal with non-monotonic vortex–vortex interactions

Abstract

The magnetic response related to the paramagnetic Meissner effect (PME) is studied in a high quality single crystal ZrB 12 with non-monotonic vortex-vortex interactions. We observe the expulsion and penetration of magnetic flux in the form of vortex clusters with increasing temperature. A vortex phase diagram is constructed, and shows that the PME can be explained by considering the interplay among the flux compression, the different temperature dependencies of the vortex-vortex and the vortex-pin interactions, and thermal fluctuations. Such a scenario is in good agreement with the results of magnetic relaxation measurements.

Universal flux patterns and their interchange in superconductors between types I and II

“…At sufficiently large fields Meissner islands eventually disappear and the Abrikosov lattice occupies all available space. These transformations of the vortex matter agree with available experimental results on IMS vortex patterns [2][3][4][5][6][7][8][9] .…”

“…It contains the upper part (κ ≳ κ 0 ), with the "solid" vortex matter, and the lower part (κ ≲ κ 0 ), where the vortex matter liquefies, with the division line κ ≈ κ 0 marking the onset of the stability of single vortex states 21,22 . Until now experimental studies dealt with the materials in the upper part of the diagram, such as Nb 9 and ZrB 12 8 , and our results fully explain observed solid vortex clusters. However, the vortex liquid and giant vortices in the lower part of the diagram remain to be studied experimentally.…”

“…Detailed investigations of the magnetic response revealed a class of materials with κ~1 whose magnetic properties belong to neither of these two common types [2][3][4][5][6][7][8][9] . Experiments demonstrated that such crossover or inter-type (IT) materials develop the so-called intermediate mixed state (IMS), where the magnetic field penetrates a superconductor but forms a rich manifold of exotic spatial configurations made of Meissner domains coexisting with islands of the vortex lattice, vortex clusters, chains, etc.…”

Coexistence of type-I and type-II superconductivity signatures in ZrB12 probed by muon spin rotation measurements

“…The magnetic field distribution observed at 5.2 K and 50 Oe [see Fig. 1(b)] is very similar to an intermediate state of a type-I superconductor (interestingly, the study [31,42] reported vortices at these temperatures). Besides the background peak at 50 Oe, we also observe a peak at higher field ≈60 Oe, as well as a peak at B = 0, indicating the presence of areas of expelled magnetic flux.…”

Synthesis and Characterization of Single-Phase Metal Dodecaboride Solid Solutions: Zr1–xYxB12 and Zr1–xUxB12

“…Dodecaborides were reported to exhibit superconducting transition temperatures in the sub 6 K range. [94][95][96][97] (Zr0.5Y0.5)B12 (synthesized as (Zr0.5Y0.5):13B, Tc = 2.5 K) does not fall between YB12…”