Weak pinning and vortex bundles in anisotropic Ca$_{10}$(Pt$_4$As$_8$)[(Fe$_{1-x}$Pt$_x$)$_2$As$_2$]$_5$ single crystals

O. E. Ayala-Valenzuela; N. Haberkorn; A. B. Karki; Jisun Kim; R. Jin; Jeehoon Kim

paper

Weak pinning and vortex bundles in anisotropic Ca $_{10}$ (Pt $_{4}$ As $_{8}$ )[(Fe $_{1 - x}$ Pt $_{x}$ ) $_{2}$ As $_{2}$ ] $_{5}$ single crystals

arXiv:1501.07677

Abstract

We report the magnetic field -- temperature ( $H - T$ ) phase diagram of Ca $_{10}$ (Pt $_{4}$ As $_{8}$ )[(Fe $_{1 - x}$ Pt $_{x}$ ) $_{2}$ As $_{2}$ ] $_{5}$ ( $x \approx 0.05$ ) single crystals, which consists of normal, vortex liquid, plastic creep and elastic creep phases. The upper critical field anisotropy is determined by a radio frequency technique via the measurements of magnetic penetration depth, $λ$ . Both, irreversibility line, $H_{i r r} (T)$ , and flux creep line, $H^{S P M} (T)$ , are obtained by measuring the magnetization. We find that $H_{i r r} (T)$ is well described by the Lindemann criterion with parameters similar to those for cuprates, while small $H^{S P M} (T)$ results in a wide plastic creep regime. The flux creep rates in the elastic creep regime are in qualitative agreement with the collective creep theory for random point defects. A gradual crossover from a single vortex to a bundles regime is observed. Moreover, we obtain $λ (4 K) = 260 (26)$ nm through the direct measurement of the London penetration depth by magnetic force microscopy.

Weak pinning and vortex bundles in anisotropic Ca10​(Pt4​As8​)[(Fe1−x​Ptx​)2​As2​]5​ single crystals

Abstract

Weak pinning and vortex bundles in anisotropic Ca $_{10}$ (Pt $_{4}$ As $_{8}$ )[(Fe $_{1 - x}$ Pt $_{x}$ ) $_{2}$ As $_{2}$ ] $_{5}$ single crystals