Synthesis of Cobalt Grown from Co-S Eutectic in High Magnetic Fields
Steven Flynn, Caeli L. Benyacko, Matúš Mihalik, Jared Lee, Fuyan Ma, Michael E. Bates, Shubham Sinha, Khalil A. Abboud, Marian Mihalik, Mark W. Meisel, James J. Hamlin
Published: 2025/4/1
Abstract
Samples of Co were grown directly in the ferromagnetic state under equilibrium conditions using a cobalt sulfide flux. Magnetic fields up to 9 T were applied during growth, and isolated Co products exhibit progressively elongated morphologies, from cubes to rectangular rods to needle-like tendrils with poorly-defined facets. The degree of elongation of the major axis was found to correlate with magnetic field direction, strength, and gradient. Two-dimensional X-ray diffraction data indicate some level of polycrystalline-like samples, and quantitative analyses (Le Bail and Rietveld) of the one-dimensional data confirm the presence of hcp and fcc phases. The magnetic responses indicate a partial alignment of the magnetic easy-axis of the hcp phase along the magnetic field present during growth.