A 28 GHz microwave heating method was used to react an Fe2O3 + Y2O3 po
wder mixture to form yttrium iron garnet (YIG, Y3Fe5O12) powder. The m
inimum temperature to form YIG was lower than the conventional (extern
al) heating method. YIG began to form after only 70 s of irradiation,
which means that the solid-state reaction proceeded very rapidly. The
amounts of byproducts were controlled by the starting composition and
by the Y2O3 particle size. The resultant YIG particle size also was co
ntrolled by the Y2O3 particle size.