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 T_c ≈ 3-5 K above P_c ≈ 6 GPa, the antiferromagnetic transition temperature T_N(P) experiences a quicker rise with the slope increased dramatically from dT_N/dP = 0.85(14) K/GPa for P ≤ P_c to 3.7(2) K/GPa for P ≥ P_c. 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.