Isolation of proximity-induced triplet pairing channel in a superconductor/ferromagnet spin valve

¹ Zavoisky Physical-Technical Institute, Russian Academy of Sciences, 420029 Kazan, Russia
² L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, Chernogolovka, Russia
³ Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
⁴ Leibniz Institute for Solid State and Materials Research IFW Dresden, D-01069 Dresden, Germany
⁵ Institute for Solid State Physics, Technical University Dresden, D-01062 Dresden, Germany

^* e-mail: kamandi@mail.ru

Published online: 4 July 2018

Abstract

In the present work we have studied the proximity-induced superconducting triplet pairing in CoO_x/Py1/Cu/Py2/Cu/Pb spin-valve structure (where Py = Ni_0:81Fe_0:19). For CoO_x(3 nm)/Py(3 nm)/Cu(4 nm)/Py(0.6 nm)/Cu(2 nm)/Pb(70 nm) we have studied the dependence of the T_c on the angle α between the direction of the cooling field and the external field both applied in the plane of the sample. We obtained that the T_c does not change monotonically with the angle but passes through a minimum. To observe an “isolated” triplet spin-valve effect we exploited the oscillatory feature of the magnitude of the ordinary spin-valve effect ΔT_c in the dependence of the Py2-layer thickness d_Py2. We determined the value of d_Py2 at which ΔT_c caused by the ordinary spin-valve effect is suppressed. This means that the difference in the T_c between the antiparallel and parallel mutual orientation of magnetizations of the Py1 and Py2 layers is zero. For such a sample a “pure” triplet spin-valve effect which causes the minimum in T_c at the orthogonal configuration of magnetizations has been observed.