One-step synthesis of FePt nanoparticles with tunable size.

A one-step synthesis of FePt nanoparticles is reported. The size, composition, and shape of the particles are controlled by varying the synthetic parameters such as molar ratio of stabilizers to metal precursor, addition sequence of the stabilizers and metal precursors, heating rate, heating temperature, and heating duration. An assembly of large (6 nm or greater) FePt nanoparticles, especially oxide-coated FePt nanoparticles, can sustain higher temperature (up to 650 degrees C) annealing without noticeable particle sintering. Room temperature coercivity of an assembly containing discrete FePt dots can reach as high as 1.3 T, a value that is suitable for hard magnetic applications.