Investigation of spin-polarized carrier injection effect in YBa_2Cu_3O_7/SrTiO_3/La_(0.67)Sr_(0.33)MnO_3 and YBa_2Cu_3O_7/La_(0.67)Sr_(0.33)MnO_3 heterostructures

摘要

We report preparation and electrical properties of the YBa_2Cu_3O_7/SrTiO_3 (d approx = 5.0 nm)/La_(0.67)Sr_(0.33)MnO_3 (YBCO/STO/LSMO) and YBCO/LSMO multilayer structures grown heteroepitaxially on LaAlO_3(100) substrates by single source pulsed injection MOCVD. The heterostructures were patterned in a cross-strip geometry to perform electrical measurements at T = 78 ÷ 300 K under magnetic field μ_0H = 0 ÷ 16 T using 4-probe dc method. Suppression of a supercurrent of the patterned YBCO stripes was indicated for the YBCO/LSMO heterostructure by injecting tunneling spin-polarized current from the underlying FM layer. The transport effects were modelled taking into account current redistribution in the adjacent conducting HTS and FM layers.