Magnetic behavior of chemically synthesized FePt–FeRh nanostructures

We describe here the chemical synthesis and magnetization behavior of FeRh–FePt nanostructures fabricated using a two-step procedure. The first step involved chemical synthesis of FeRh nanoparticles using a polyol co-reduction process accompanied by the second stage of encapsulation of FeRh nanoparticles with FePt. The FeRh–FePt nanoparticles were subsequently annealed in a salt matrix at 600 °C for 3 h. Magnetic measurements were made on films of FeRh–FePt nanostructures cast onto silicon wafers before and after the salt matrix annealing. The coercivity of as-synthesized FeRh–FePt nanostructures was ∼70 Oe at room temperature, while the coercivity of salt-matrix annealed FeRh–FePt nanoparticles was ∼7065 Oe. The temperature dependent magnetization measurement of annealed FeRh–FePt nanostructures indicated antiferromagnetic–ferromagnetic transition that is supported by X-ray diffraction study. The observations point toward the potential realization of FeRh–FePt nanostructures for ultra-high density magnetic recording media.