Mixed nickel-gallium tellurides Ni3-xGaTe2 as a matrix for incorporating magnetic cations: A Ni3-xFexGaTe2 series

Using a high-temperature ampoule technique, a series of mixed nickel-iron-gallium metal-rich tellurides with layered structures, Ni3-xFexGaTe2, were prepared and characterized based on X-ray powder diffraction, energy dispersive spectroscopy, and Fe-57 Mossbauer spectroscopy data. These compounds may be regarded as a result of partial substitution of nickel by iron in the recently reported ternary Ni3-xGaTe2 series, which are based on NiAs/Ni2In type of structure. The compositional boundary for the substitution was found to be at x similar to 1. According to the Mossbauer spectroscopy data, the substitution is not statistical, and iron atoms with the increase in x tend to preferentially occupy those nickel positions that are partially vacant in the initial ternary compound. Magnetic measurements data for the Ni3-xFexGaTe2 series show dramatic change in behavior from temperature-independent paramagnetic properties of the initial matrix to a low-temperature (similar to 75 K) ferromagnetic ordering in the Ni2FeGaTe2.