Pressured-induced superconducting phase with large upper critical field and concomitant enhancement of antiferromagnetic transition in EuTe2

Abstract

We report an unusual pressure-induced superconducting state that coexists with an antiferromagnetic ordering of Eu2+ moments and shows a large upper critical field comparable to the Pauli paramagnetic limit in EuTe2. In concomitant with the emergence of superconductivity with Tc ≈ 3–5 K above Pc ≈ 6 GPa, the antiferromagnetic transition temperature TN(P) experiences a quicker rise with the slope increased dramatically from dTN/dP = 0.85(14) K/GPa for P ≤ Pc to 3.7(2) K/GPa for P ≥ Pc. Moreover, the superconducting state can survive in the spin-flop state with a net ferromagnetic component of the Eu2+ sublattice under moderate magnetic fields μ0H ≥ 2 T. Our findings establish the pressurized EuTe2 as a rare magnetic superconductor possessing an intimated interplay between magnetism and superconductivity.