Frequency Dependence of Elastic Constants and Losses in Nickel

摘要: The elastic constants of nickel crystals, and their variation with magnetic field (ΔE effect), have been measured by a 10-megacycle ultrasonic pulsing method. three crystals agree well one another when the are magnetically saturated, but vary domain distribution demagnetized. maximum ΔE effect observed is much less (3%) than has at lower frequencies (20%). By measuring decrement polycrystalline rods low frequencies, it shown that small 10 megacycles due to relaxation in wall motion microeddy-current damping. From initial slope decrement-frequency curve, also from frequency decrement, size average found he about 0.04 mm. Actual domains single optically Williams, who finds widths 0.02 0.2