The IrMn/Py/Ru/Co (Py = Ni81Fe19) spin valves have been produced by sputtering deposition and analyzed by magnetization measurements and a theoretical modelling of their exchange interactions, based on the macro-spin model. The Ru thickness was grown between 6 and 22 Å, which is small enough to promote strong indirect coupling between Py and Co. Results of measurements showed a large and gradual change in the shape of hysteresis loops when the Ru thickness was varied. The theoretical analysis, using numerical calculations based on the gradient conjugate method, provides the exchange coupling constants (bilinear and biquadratic), the exchange anisotropy fields and the magnetic anisotropy fields (uniaxial and rotatable). The exchange bias fields of spin valves were compared to that of a IrMn/Py bilayer. We found that the difference between these fields oscillates with Ru thickness in the same manner as the bilinear coupling constants.
Bibliographical noteFunding Information:
This work has been partially supported by the Brazilian agencies CNPq and CAPES . H.S.T. thanks to the Peruvian Doctoral Scholarship of CIENCIACTIVA (CONCYTEC) under Grant # 218-2014-FONDECYT . C.V.L. and J.Q-M are grateful to CIENCIACTIVA (CONCYTEC) for financial support throught the Excellence Center Programs. We also acknowledge E.B. Saitovitch and CBPF for experimental facilities.
- Exchange coupling
- Magnetic anisotropy
- Spin valves