Effects of proton irradiation on the magnetic superconductor EuFe <sub>2</sub> (As <sub> 1 − <i>x</i> </sub> P <sub> <i>x</i> </sub> ) <sub>2</sub>
G. Ghigo, Daniele Torsello, Roberto Gerbaldo, L. Gozzelino, Sunseng Pyon, I. S. Veshchunov, T. Tamegai, Guang‐Han Cao
Abstract
Abstract We report on the effects of 3.5 MeV proton irradiation on single crystals of the magnetic superconductor EuFe 2 (As 1 − x P x ) 2 , investigated at microwave frequencies by a coplanar waveguide resonator technique. We studied the relative strength of the two collective phenomena by analyzing the dependence of their onset temperatures on different perturbations: magnetic fields and structural disorder. Results suggest that superconductivity and magnetism in this material are two competing orders: as the former is suppressed by irradiation or by excess P doping, the latter reinforces and manifests itself at higher temperatures. The ability to modulate superconductivity and magnetism in EuFe 2 (As 1 − x P x ) 2 by disorder and in-plane magnetic field, respectively, offers the chance to tailor, even on a local scale, their relative weights. This could be useful for the aim of engineering this material for specific applications.