Cobalt Ferrite Crystal Growth from the Ternary Flux System Na2O–CoO–Fe2O3

Abstract

It is shown that the simple ferrite spinels (M²⁺Fe₂O₄) crystallize readily from the ternary flux system MO–Na₂O–Fe₂O₃. The liquidus‐solidus phase diagrams for the pseudobinary of Na₂Fe₂O₄–CoFe₂O₄ and the ternary Na₂O–CoO–Fe₂O₃ are presented. A general discussion of flux growth of ferrite crystals of both the simple spinel type and the more complex layered structures (BaFe₁₂O₁₉) is given. Crystals of CoFe₂O₄ were grown from a mixture of 1.5 moles of CoFe₂O₄ and 1 mole of Na₂Fe₂O₄ by utilizing a platinum wire cold finger.