Size-dependent properties of single domain FeCoGa nanoparticles prepared by a facile template-less chemical route

Single phase X type Fe 2 CoGa Heusler alloy nanoparticles with average crystallite sizes of 56 nm, 26 nm, and 21 nm have been synthesized using a refined template-less chemical route. Size-dependent structural and magnetic properties of the Fe 2 CoGa alloy nanoparticles are compared with the bulk counterpart prepared by arc melting. Fe 2 CoGa nanoparticles show soft ferromagnetic behavior with high magnetic moment and Curie temperature. Ab initio calculations have been carried out to interpret the experimental results. The estimated critical size and measured magnetic properties of the nanoparticles reveal that the synthesized nanoparticles are in a single domain superparamagnetic regime. Coercivity of Fe 2 CoGa nanoparticles is superposed on typical single domain nanoparticle pattern. Magnetic hysteresis loop depicts superparamagnetism. HRTEM images show lattice fringes from (111) and (200) planes of inverse Heusler alloy structure.