2018 Volume 42 Issue 3 Pages 78-82
Ni(tNi nm)/Ni50Co50(100–tNi nm) bi-layer films are prepared on Cu/Pd/MgO(001) single-crystal substrates at 300 ℃ and on Cu/Pd/glass substrates at room temperature by varying the layer thickness, tNi, in a range of 0–100 nm. The effect of layer thickness ratio on the magnetostriction is investigated. As tNi value increases from 0 to 100 nm, the magnetostriction coefficient observed for single-crystal film along fcc[100], λ100, monotonically decreases from a positive value of +1 × 10–4 (tNi = 0 nm) to a negative value of –6 × 10–5 (tNi = 100 nm), whereas that measured along fcc[111], λ111, remains almost similar (–4 × 10–5 to –2 × 10–5). The magnetostriction coefficient of poly-crystalline film decreases from –3 × 10–6 to –2 × 10–5 with increasing tNi value from 0 to 100 nm. The present study has shown that control of magnetostriction coefficient is possible by combining materials with positive and negative coefficients.