HIP synthesis of η-carbide-type nitrides Fe3W3N and Fe6W6N and their magnetic properties

We have succeeded in synthesising iron–tungsten nitrides using the hot isostatic pressing (HIP) method and have measured their magnetic properties. Two η-carbide-type iron–tungsten nitrides with lattice constants a = 11.043(1) and 10.937(2) Å were synthesised directly from metal elements under high-pressure nitrogen gas. Their compositions are expected to be Fe3W3N and Fe6W6N in analogy with other η-carbide-type compounds. Fe3W3N is a ferromagnet with a Curie temperature TC = 110 K and a saturation moment PS = 0.78μB/Fe, whereas Fe6W6N is an antiferromagnet with a Néel temperature TN = 75 K and shows a metamagnetic transition at around 25 T.

► Fe3W3N and Fe6W6N are successfully synthesised from powder elements using HIP method.
► Fe3W3N is a ferromagnet with TC = 110 K.
► Fe6W6N is an antiferromagnet with TN = 75 K.