Composition gradient, structure, stress, roughness and magnetic properties of 5–500 nm thin NiFe films obtained by electrodeposition

• The composition of electrodeposited NiFe changes in the thickness range 5–250 nm.
• Properties of NiFe films are influenced by the composition gradient observed.
• The mechanisms of coercivity change on different substrates are discussed.
• Magnetostriction, stress, grain size, and roughness are the keys for properties.

The composition gradients of 5–500 nm thin NiFe films on Cu and NiP substrates obtained by electrodeposition in stirred plating solutions at pH 3.0 on 8 in wafers were studied. It was found that the average elemental composition of the NiFe changes during electrodeposition with steep downturns of Fe-content, from 58 to 50 wt% Fe, in composition gradient zone near the substrate interface in the thickness range 5–250 nm depending on the electrode substrate (Cu and NiP). The increase of Fe-content in the composition gradient zone is accompanied by the increase of coercivity, Hc, magnetic flux saturation, Bs, saturation magnetostriction, λs, increase of dimensionless roughness, ρrms, and change of stress, σ. The coercivity (easy and hard axis) follows the Neel's relation Hc=ct−n (t is thickness and c is a constant). The mechanisms related to the change of coercivity of the NiFe films deposited on different substrates (Cu and NiP) are discussed in terms of material properties of these films.