Abstract

Nanocrystalline powders of MnFeP_1-xAs_x(x=0.45-0.6) have been synthesized by mechanochemical reaction at room temperature using high-energy ball milling from mixtures of Mn, Fe, P, and As Powders. It has been found that a mechanically induced self-propagating reaction (MSR) occurs within 2 hours of milling and it produces very fine polycrystalline powder having a hexagonal Fe_2P structure. Further milling up to 24 hours did not change the crystalline and average particle sizes or the phase composition of the milling product. When x is 0.65, no reaction among the reactants has been observed even after 24 hours of milling. As the P content decreases in MnFeP_1-xAs_x, the incubation time for the MSR has increased and the lattice constants in both a and c axes have changed.

• Keywords: Mechanochernical processing;High energy ball milling;Nanocrystalline powder;Transition metal pnictide;