The Preparation Of Micrometer YIG Films Used For Circulator By Pulsed Laserd Eposition

Circulator is one of widely used microwave devices in military and civil fields.Conventional circulators are all fabricated on bulk ferrite materials, which lead toheavy mass and big volume of circulators. Nowadays, the modern equipments aremore and more sensitive to the volume and mass of the devices, so developing acirculator with smaller mass and volume is very necessary. Film microwave circulatorwas proposed in this background. Though much research had been done, the filmcirculator preparation technology is still very immature. It’s very difficult to preparehigh quality ferrite thick films, which are one of the adverse factors for the study offilm microwave circulator.This study is to prepare high quality films using pulsed laser deposition technique.Firstly, the influences of deposition temperature and oxygen pressure on themicrostructure, magnetization and ferromagnetic resonance (FMR) line width arediscussed. In this research, the best conditions to prepare YIG films were obtained.Secondly, according to the best conditions, the YIG films were deposited on MgO andsapphire substrates, which proved that the MgO and sapphire substrates could be usedto prepare YIG films. At last, YIG films thicker than10μm were deposited on silicon,GGG, MgO and sapphire substrates. Two conclusions can be summarized from thestudy to prepare YIG films thicker than10μm. First, because of the high misfit oflattice constant and coefficient of thermal expansion between silicon or sapphire andYIG, it’s difficult to prepare high quality thick YIG films on silicon and sapphiresubstrates. Second, GGG and MgO are good substrates to prepare high quality thickYIG films.