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Selected Works of Takele Seda
Article
Synthesis and Characterization of Discrete FexNi2–xP Nanocrystals (0 < x < 2): Compositional Effects on Magnetic Properties
Chemistry of Materials (2015)
  • Asha Hitihami-Mudiyanselage, Wayne State University
  • Maheshika Palihawadana Arachchige, Wayne State University
  • Takele Seda, Western Washington University
  • Gavin Lawes, Physics, Nano Incubator Program
  • Stephanie L. Brock, Chemistry, Nano Incubator Program
Link
Abstract
Ternary FexNi2–xP (0 < x < 2) phases exhibit a range of useful properties that can be augmented or tuned by confinement to the nanoscale including hydrotreating catalytic activity for small x and near-room temperature ferromagnetism for high x. In this work, a solution-phase arrested-precipitation method was developed for the synthesis of FexNi2–xP over all values of x (0 < x < 2). The synthesis involves preparation of Ni–P amorphous particles, introduction of the Fe precursor to form amorphous Fe–Ni–P particles, and high-temperature conversion of Fe–Ni–P particles into crystalline ternary phosphide nanocrystals. The ternary FexNi2–xP nanocrystals crystallize in the hexagonal Fe2P-type structure, and the morphology of the nanocrystals showed a distinct compositional dependence, transitioning from about 11 nm diameter spheres to rods with aspect ratios approaching 2 as the Fe fraction is increased (x ≥ 1.2). Lattice parameters do not follow Vegard’s law, consistent with Mössbauer data showing preferential site occupation by Fe of the tetrahedral over the square pyramidal sites at low Fe concentrations, and the opposite effect for x> 0.8. Magnetic measurements of FexNi2–xP (x = 1.8, 1.4, and 1.2) nanorods showed a strong compositional dependence of the Curie temperature (TC) that differs from observations in bulk phases, with the highest TC (265 K) obtained for x = 1.4.
Keywords
  • Magnetic properties
Disciplines
Publication Date
October 13, 2015
DOI
10.1021/acs.chemmater.5b02149
Publisher Statement
Copyright 2019 American Chemical Society
Citation Information
Synthesis and Characterization of Discrete FexNi2–xP Nanocrystals (0 < x < 2): Compositional Effects on Magnetic Properties. Asha Hitihami-Mudiyanselage, Maheshika Palihawadana Arachchige, Takele Seda, Gavin Lawes, and Stephanie L. Brock, Chemistry of Materials 2015 27 (19), 6592-6600 DOI: 10.1021/acs.chemmater.5b02149