Abstract
Effects of annealing temperature on the crystalline and magnetic properties of YIG films grown by solid phase epitaxy. The eptiaxy films were made by annealing Fe-Y-O amorphous films in the air at 550-1050 $^{\circ}C$ which were sputtered on GGG (111) substrates in a conventional rf sputtering system. Crystallization temperature of Fe-Y-O amorphous films on GGG (111) substrate was between 600 and 650 $^{\circ}C$ which is much lower than that Fe-Y-O powder prepared by sol-gel method. Excellent epitaxial growth of YIG films could be conformed by the facts that the diffraction intensity of YIG (888) plane was comparable with that of GGG (888) plane and full width at half maximum of YIG (888) rocking curve was smaller than 0.14$^{\circ}$ when films were annealed at 1050 $^{\circ}C$. It could be seen that it is necessary to anneal the films at higher temperature for an excellent epitaxy because lattice parameter of YIG films were smaller and the peak of YIG (888) plane is higher and narrower with increasing annealing temperature. Films annealed at higher temperature shows M-H loop with perpendicular anisotropy which was due to 0.15％ lattice mismatch between YIG and GGG.
통상적인 rf 스파터 장비와 YIG 타켓으로 수 $\mu\textrm{m}$의 Fe-Y-O 비정질상을 Ga-Gd Garnet(GGG) (111) 기판위에 만든 다음 550-105$0^{\circ}C$의 온도에서 대기 중 열처리할 때 열처리온도가 결정특성과 자기특성에 미치는 영향을 조사하였다 .Fe-Y-O 비정질상의 결정화온도는 졸-겔 분말의 결정화온도보다 훨씬 낮은 600-$650^{\circ}C$이었으며, $650^{\circ}C$ 이상에서 열처리하면 YIG(888)면의 피크의 강도는 GGG(888) 면 회절강도의 80%정도이고 YIG(888)면의 록킹곡선의 반가폭도 0.14$^{\circ}$보다 작아 YIG박막의 우수한 에피택시성장을 확인하였다. 열처리온도가 높을 경우 격자상수가 작아지면서 YIG(888)면의 회절선이 강해지고 좁아져서 높은 온도가 YIG박막의 고상에피택시성장에 유리하였으며 이것은 자화곡선에서도 확인되었다. 또한 높은 온도에서 열처리된 박막에서 수직이방성이 유도되었으며 이것은 기판과 박막의 0.15%의 격자불일치 때문에 생기는 것이다.
