Effect of ferromagnetism on superconductivity in manganite/cuprate heterostructures

In this investigation, we deposited multilayers of [(La0.67Sr0.33MnO3)d/(YBa2Cu3Oy)x], [(La0.7Ca0.3MnO3)4/(YBa2Cu3O7)x]180nm and [(La0.45Ca0.55MnO3 )4/(YBa2Cu3O7)x]180nm of varying individual layer thicknesses using the 'eclipse' pulsed laser deposition technique. Transport measurements were performed to obtain the films' critical temperatures (Tc). We study the interaction between superconductivity and magnetism within these heterostructures, paying attention to the superconducting and ferromagnetic coherence lengths, ξF and ξS respectively, of the materials in the system, and analyzing how these parameters affect the suppression of Tc, eliminating stray field as a possible cause of Tc suppression. We compared our data to previous work to achieve a more comprehensive study of oxide F/S multilayers. We observe that the magnetic nature of the manganite layers do not have much influence on Tc suppression in the multilayers. We show that within certain limits, the thicknesses of both the superconducting and ferromagnetic layers individually affect the Tc of the multilayers. The critical thickness of YBCO in our multilayers was estimated to be ∼20 nm