Barium Hexaferrite Thick Films Made by Liquid Phase Epitaxy Reflow Method

Abstract

In this paper, we report on the growth of BaFe <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$_12$</tex> O <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$_19$</tex> (BaM) thick films on sapphire Al <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$_2$</tex> O <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$_3$</tex> (0001) substrate. Our goal is to fabricate barium ferrite thick films which can be self-biased for circulator applications. We have modified the liquid phase epitaxy (LPE) method by conducting the experiment in vacuum. A small piece of the melt weighing approximately 0.035 g was placed on 1 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$,times,$</tex> 1 cm Al <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$_2$</tex> O <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$_3$</tex> substrate and remelted at 1200 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$^circ$</tex> C for 1 h. The thickness of our thick films grown by this reflow method range from 300 to 550 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$mu$</tex> m. The coercivities of the thick films in the perpendicular direction were about 100 Oe.