Observation of Well-Ordered Metastable Vortex Lattice Phases in SuperconductingMgB2Using Small-Angle Neutron Scattering

Structural studies of metastable and equilibrium vortex lattice domains in MgB2

“…In principle it is also possible to infer an in-plane correlation length from the width of the VL Bragg peaks in the plane of the detector. However, due to the two orders of magnitude poorer azimuthal resolution (see section 2) this yields ζ A =2/q w A ∼0.1 μm [6]. which should only be taken as a lower limit on the domain size.…”

“…We used the same 200 μg single crystal of MgB 2 (T 38 K c = , H 3.1 T 0 c2 m = ) as in prior SANS studies [6,7]. The sample was grown using a high pressure cubic anvil technique that has been shown to produce good quality single crystals [16], and isotopically enriched 11 B was used to decrease neutron absorption.…”

“…The presence of metastable non-equilibrium vortex lattice (VL) phases in superconducting MgB 2 is well established [6,7]. The equilibrium VL phase diagram for this material, shown in figure 1(a), displays three triangular configurations, denoted F, L and I, differing only in their orientation relative to the hexagonal crystalline axes [6,8]. In the F ( figure 1(b)) and I phases a single global orientational order is observed, with the VL nearest neighbor direction along the a* and a directions within the basal plane respectively.…”

“…In the intermediate L phase (figure 1(c)), the VL rotates continuously from the a to the a* orientation, giving rise to two degenerate domain orientations. Cooling or heating across the F-L or L-I phase boundaries leaves the VL in a MS, as thermal excitations are insufficient to drive the system to equilibrium [6]. The metastability is not due to Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.…”

Calibrating SANS data for instrument geometry and pixel sensitivity effects: access to an extendedQrange

“…Small-angle neutron scattering (SANS) is a commonly used technique to determine the size, shape and arrangement of structures on a mesoscopic length scale in physics, chemistry, biology and materials science (Lindner et al, 2000;Wang et al, 2004;Petoukhov & Svergun, 2005;Davies et al, 2006;Schmidt-Rohr & Chen, 2008;Fratzl, 2003;Das et al, 2012;Martin et al, 2013;Milde et al, 2013;Gilles et al, 2014;Jaksch et al, 2014;Tokunaga et al, 2015;Lang et al, 2016).…”