Applied Magnetic Field Rejects the Coating of Ferromagnetic Carbon from the Surface of Ferromagnetic Cobalt:RAPET of CoZr_2(acac)_2(O~iPr)_8

摘要

We present the results of the RAPET (reaction under autogenic pressure at elevated temperatures) dissociation of CoZr_2(acac)_2(O~iPr)_8 at 700 deg C in a closed Swagelok cell under an applied magnetic field of 10 T.It produces a mixture of carbon-coated and noncoated metastable ZrO_2 nanoparticles,bare metallic Co nanoparticles,and bare carbon.The same reaction in the absence of a magnetic field produces spherical Co and ZrO_2 particles in sizes ranging from 11 to 16 nm and exhibiting,at room temperature,metastable phases:fcc for cobalt and a tetragonal phase for zirconia.The metastable phases of Co and ZrO_2 are manifested because of a carbon shell of ~4 nm thickness anchored to their surfaces.The effect of an applied magnetic field to synthesize morphologically different,but structurally the same,products is the key topic of the present paper.