Improved Interfaces and Magnetic Properties in Spin Valves Using Ni80Fe20 Seed Layer

Published

March 1, 2002

Author(s)

E J. Repetski, D X. Yang, H D. Chopra, P J. Chen, William F. Egelhoff Jr.

Abstract

The giant magnetoresistance (GMR) (Ni₈₀Fe₂₀)O-Co-Cu based top spin valves were studied with and without Ni₈₀Fe₂₀ as a seed layer. Microstructure examination shows that without the seed layer, the free and the pinned Co layers of the spin valves are highly irregular, discontinuous, and connected by pinholes across the Cu spacer layer, resulting I a large coupling >5.96 kA/m (>75 Oe) and a negligible GMR effect (<0.7%). The presence of Ni₈₀Fe₂₀ seed layer leads to continuous layers without pinholes and smooth interfaces in the (Ni₈₀Fe₂₀) O-Co-Cu, thereby essentially eliminating the coupling between the free and the pinned layers 0.23 kA/m (or 2.9 Oe), a more than 25-fold reduction with respect to the seedless spin valves. Reduced detrimental coupling results in more than an order of magnitude increase in GMR (8.5 %) in the NiFe seed layer spin valves. Domain studies confirm that the pinned and the free layers in seedless spin valves reverse their magnetization in an overlapping field range, and independently in spin valves deposited in the presence of a seed layer.

Citation

Journal of Applied Physics

Volume

91

Issue

No. 6

Pub Type

Journals

Keywords

domain study, giant magnetoresistance (GMR), interfaces, spinvalves

Citation

Repetski, E. , Yang, D. , Chopra, H. , Chen, P. and Egelhoff Jr., W. (2002), Improved Interfaces and Magnetic Properties in Spin Valves Using Ni₈₀Fe₂₀ Seed Layer, Journal of Applied Physics (Accessed October 15, 2025)