Magnetic properties of ferromagnetic Heusler alloy Co2ZrAl

Abstract A precise magnetization measurement of a ferromagnet Co 2 ZrAl with Heusler-type structure has been made under ambient pressure using a SQUID magnetometer. The magnetic moment μ S at 4.2 K and the Curie temperature T C are 0.74 μ B /f.u. and 180 K, respectively. The spontaneous magnetization σ s ( T ) at ambient pressure is expressed as a function of temperature as σ s ( T ) 2  =  σ s (0) 2 ( 1 − T 2 / T C ′ 2 ), where σ s (0) and T C′ are 17.3 emu/g and 185 K, respectively. The pressure derivative of T C has been obtained from the results of the temperature dependence of the initial permeability under pressure up to 10 kbar. The value of d T C /d p is −0.4 K/kbar. The pressure change of the spontaneous magnetization σ s at 4.2 K for Co 2 ZrAl has been determined by the subtraction method under pressure up to 10 kbar. The value of d σ s /d p is found to be -3.2 × 10 −2  emu/g kbar. The electronic structure of Co 2 ZrAl 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.