K. Ashok^1,2 U.D.Chacón Hernandez¹ J. Quispe-Marcatoma ^1,3 & E. Baggio-Saitovitch¹

¹Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180, RJ-Brazil

² Department of Physics, SRM University, Kattankulathur -603203, India

³Universidad Nacional Mayor de San Marcos, Lima. Perú. 140149

The AFM/FM bilayer, which provides the necessary exchange bias through exchange anisotropy, is the heart of a SV structure [1], and many research works are focusing on enhancing exchange bias, such as varying seed layer [2], adding surfactant [3], searching new AFM materials [4], finding the exact fabricated conditions [5,6] and so on. Double exchange biased spin valves with the structure of Ru/NiFe/FeMn/Ru/-CoFe/FeMn/Ru on Si (111) substrate were prepared by dc magnetron sputtering system. The deviation of the modified Ne´el model at the dip zone could be due to the large canting of the pinned layers, which depend on applied Field and different thickness. Aim of this paper is to review a few aspects of the material properties of Double Exchange biased spin-valves, role of ferromagnetic layer thickness responds to blocking temperature which are relevant for the use in a field sensor/recording head or in an MRAM device. We found that Exchange bias is decreasing when the FM thickness increases, at some point H_E disappears. The interfacial unidirectional energy density follows the below equation,

H_E=Δσ/M_FMt_FM                              (1)

Interface coupling due to exchange anisotropy is observed cooling the AFM -FM couple in the presence of a static magnetic field from a temperature above T_N , but below T_C (T_N<T< T_C) to temperatures T<T_N.

References

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