High-precision measurement of electrical resistivity of nickel near the ferromagnetic phase transition at high pressure.

High-precision measurement of the resistance of nickel near its ferromagnetic phase transition at high pressure was done in a large volume hydrostatic cubic multiple-anvil pressure cell between 25 and 45 kbar. A real-tine computer-controlled measurement system was developed to measure the resistance vs temperature and pressure. The values of the critical exponent a and amplitude ratio of the leading term A /A' are in good agreement with the results published by Ahlers and Kornblit from specific-heat measurement and by Kallback et al. in a resistance measurement at atmospheric pressure. They are found to be independent of pressure. The critical temperature T, increases linearly with pressure at a rate of 0.193+0.013 K/kbar. The amplitude ratio for the correction to scaling term D!D' has also been determined. There is considerable uncertainty in the measurement but the data may indicate a variation with pressure contrary to expectations of universality.