Pressure Effect on the Magnetic Properties of the Heusler Alloy Co2NbGa

Magnetization measurements were conducted on a ferromagnetic Co2NbGa with the Heusler-type structure at various pressures. The spontaneous magnetic moment (ps) at 10 K under ambient pressure was determined to be 1.79(3) μB/f.u. The values of dps/dp and dlnps/dp at 10 K were estimated to be –0.13 × 10–3 μB·f.u.–1·kbar–1 and –7.3 × 10–5 kbar–1, respectively. The pressure derivative of the Curie temperature (TC) for Co2NbGa was determined by analyzing the temperature dependence of the initial permeability under pressures ranging up to 10 kbar. At ambient pressure, Co2NbGa had a TC value of 374.8 K, with dTC/dp and dlnTC/dp values of –0.69 K·kbar–1 and –1.84 × 10–3 kbar–1, respectively. The experimental results of the pressure-dependent magnetic properties for Co2NbGa were discussed on the basis of the spin fluctuation theory for itinerant electron magnetism.