# Superconducting properties of Ba(Fe1-xNix)2As2 thin films in high magnetic fields

## TL;DR

This study investigates the electrical transport and superconducting properties of Ba(Fe1-xNix)2As2 thin films under high magnetic fields, revealing enhanced upper critical field slopes, low anisotropy, and unique vortex behavior compared to single crystals.

## Contribution

It provides new insights into the high-field superconducting behavior and vortex dynamics of Ni-doped BaFe2As2 thin films, highlighting differences from single-crystal counterparts.

## Key findings

- Higher slope of upper critical field compared to single crystals
- Small vortex liquid phase at low temperatures
- Dominance of elastic pinning by nonmagnetic defects

## Abstract

We report on electrical transport properties of epitaxial Ba(Fe1-xNix)2As2 thin films grown by pulsed laser deposition in static magnetic fields up to 35 T. The thin film shows a critical temperature of 17.2 K and a critical current density of 5.7x10^5 A/cm^2 in self field at 4.2 K while the pinning is dominated by elastic pinning at two-dimensional nonmagnetic defects. Compared to single-crystal data, we find a higher slope of the upper critical field for the thin film at a similar doping level and a small anisotropy. Also an unusual small vortex liquid phase was observed at low temperatures, which is a striking difference to Co-doped BaFe2As2 thin films.