Magnetic properties of ferromagnetic Heusler alloy Co2ZrAl

A precise magnetization measurement of a ferromagnet Co2ZrAl with Heusler-type structure has been made under ambient pressure using a SQUID magnetometer. The magnetic moment μS at 4.2 K and the Curie temperature TC are 0.74μB/f.u. and 180 K, respectively. The spontaneous magnetization σs(T) at ambient pressure is expressed as a function of temperature as σs(T)2 = σs(0)2(1−T2/TC′2), where σs(0) and TC′ are 17.3 emu/g and 185 K, respectively. The pressure derivative of TC has been obtained from the results of the temperature dependence of the initial permeability under pressure up to 10 kbar. The value of dTC/dp is −0.4 K/kbar. The pressure change of the spontaneous magnetization σs at 4.2 K for Co2ZrAl has been determined by the subtraction method under pressure up to 10 kbar. The value of dσs/dp is found to be -3.2 × 10−2 emu/g kbar. The electronic structure of Co2ZrAl has been calculated by the linear muffin-tin orbital and the atomic sphere approximation (LMTO-ASA) method at various lattice parameters. The results are discussed on the basis of the spin fluctuation theory for itinerant electron magnetism.