Thickness controlled proximity effects in C-type antiferromagnet/superconductor heterostructure

Modulation of the superconducting state possessing a C-type antiferromagnetic phase in the Nd0.35Sr0.65MnO3/YBa2Cu3O7 heterostructure is investigated, with the Nd0.35Sr0.65MnO3 thickness (t) varying from 40 to 200 nm. Both the superconducting transition temperature and the upper critical field along the c-axis decrease with increasing t; while the in-plane coherence length increases from 2.0 up to 3.6 nm. Meanwhile, the critical current density exhibits a field-independent behavior, indicating an enhanced flux pinning effect. Furthermore, low-temperature spin canting induces a breakdown and re-entrance of the superconductivity, demonstrating a dynamic completion between the superconducting pairing and the exchange field. An unexpected colossal magnetoresistance is observed below the superconducting re-entrance temperature at t = 200 nm, which is attributed to the dominant influence of the exchange field over the pairing energy.