Magnetic Anisotropy and Magnetoresistance Properties of Co/Au Multilayers

Abstract

We report on the magnetic anisotropy (MA) and magnetoresistance (MR) properties of [Co (t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Co</sub> )/Au (t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Au</sub> )] <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</sup> multilayers prepared by changing the incident angle of deposition, θ, thicknesses t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Co</sub> and t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Au</sub> of Co and Au layers, respectively, and number of bilayers, N, while keeping N × t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Co</sub> fixed at 20 nm. Although all of the multilayers showed MAs at low applied magnetic fields, H, and room temperature, the ones deposited at θ = 45° showed remarkable magnetic anisotropies, which is further enhanced upon magnetic annealing. The [Co (1 nm)/Au (2 nm)] <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">45</sup> multilayer showed a maximum MR of 2.1% at room temperature and H = 1 kOe. Moreover, for the same field H and current I, the transverse (H ⊥ I) MR is always larger than the longitudinal (H ∥ I) MR.