Abstract
Nanocrystalline (Ni1-xCox)(0.85)Se with 0.0 <= x <= 1 solid solutions were prepared by a simple hydrothermal route. All samples form a NiAs-type hexagonal structure with metal vacancies. From Rietveld analysis, the lattice parameters are found to decrease nonlinearly with composition x; crystallite size and microstrain vary anisotropically. Magnetic measurements show that Ni0.85Se and Co0.75Se samples exhibit ferromagnetic properties while (Ni0.5Co0.5)(0.85)Se shows a paramagnetic behavior at room temperature. For the first time, nano-Ni0.85Se is reported to be ferromagnetic. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.