The results of the dynamic measurements of Young's modulus and its change with magnetization (the ΔE-effect) as well as of the ballistic measurements of the ferromagnetic characteristics made at ordinary temperatures on annealed ferromagnetic nickel-copper alloys are described. The ΔE-effect in alloys containing 5 to 20 percent copper shows a negative small minimum at low fields or at low magnetization. It is shown that the observed values of the saturation ΔE-effect are in a quantitatively fairly good agreement with values computed from a formula : - (ΔE/E_0)_s=0.7×κ_0E_0λ_s^2/I_s^2/(1-0.7×κ_0E_0λ_s^2/I_s^2), where κ_0 is the initial susceptibility, I_s the saturation magnetization, and λ_s the saturation magnetostriction. Young's moduli at unmagnetized state as well as at magnetically saturated state reveal minima at 15 to 20 percent copper. Some new information is also given of the magnetic properties.
Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy 6 446-457, 1954