Dual role of an ac driving force and the underlying two distinct order–disorder transitions in the vortex phase diagram of Ca 3 Ir 4 Sn 13

Abstract

We present distinct demarcation of the Bragg glass (BG) to multi-domain vortex glass (VG) transition line and the eventual amorphization of the VG phase in a weakly pinned single crystal of the superconducting compound Ca3Ir4Sn13 on the basis of comprehension of the different yields about the second magnetization peak (SMP) anomaly in the dc magnetization and the corresponding anomalous feature in the ac susceptibility measurements. The shaking by a small ac magnetic field, inevitably present in the ac susceptibility measurements, is seen to result in contrasting responses in two different portions of the fieldtemperature (H, T) phase space of the multi-domain VG. In one of the portions, embracing the BG to VG transition across the onset of the SMP anomaly, the ac drive is surprisingly seen to assist the transformation of the well ordered BG phase to a lesser ordered VG phase. The BG phase exists as a superheated state over a small portion of the VG space and this attests to the first order nature of the BG to VG transition.

Evidence of surface superconductivity and multi-quanta vortex states in a weakly-pinned single crystal of Ca3Ir4Sn13

“…[14]. The direction of magnetic field was maintained parallel to the plane of the platelet shaped sample, i.e., normal to its smallest dimension (i.e., thickness).…”

“…The dc magnetization data (MðHÞ=MðTÞ) in Ca 3 Ir 4 Sn 13 [14] revealed a long tail surviving beyond the irreversibility field/temperature (H irr /T irr ), in contrast to the anticipated linear variation of MðHÞ (or MðTÞ) as a function of H (or T) up to the end of the superconducting region.…”

“…We have recently explored [14] the vortex phase diagram in a single crystal of another low T c superconducting compound, Ca 3 Ir 4 Sn 13 , which is isostructural to Ca 3 Rh 4 Sn 13 [10,15]. The dc magnetization data (MðHÞ=MðTÞ) in Ca 3 Ir 4 Sn 13 [14] revealed a long tail surviving beyond the irreversibility field/temperature (H irr /T irr ), in contrast to the anticipated linear variation of MðHÞ (or MðTÞ) as a function of H (or T) up to the end of the superconducting region.…”

“…A field-temperature line, viz., (H Ã ; T Ã ), was drawn in the vortex phase diagram of Ca 3 Ir 4 Sn 13 [14], which runs parallel to the H c2 ðTÞ line. The two field-temperature lines, (H Ã ; T Ã ) and H c2 ðTÞ, intersect the temperature axis at T % 6:85 K and T c % 7:1 K, respectively in Ca 3 Ir 4 Sn 13 .…”

Unveiling of Bragg glass to vortex glass transition by an ac driving force in a single crystal of Yb3Rh4Sn13

“…Such a transition usually reflects as a second peak in (isothermal) magnetization (M -H) loops, termed as the second magnetization peak (SMP) anomaly [5][6][7][8][9][10][11]. Thereafter, at elevated fields closer to the upper critical field (H c2 (T )), there occurs another anomaly, known as the quintessential peak effect (PE) phenomenon [3,9,10,[12][13][14][15][16][17][18] in field/temperature variation in critical current density, j c (H, T ). The PE is argued [12] to signal the collapse of the elasticity of an ordered vortex lattice at a rate faster than the pinning force density near H c2 (T ).…”