(Dy,Tb)FeCo 磁光薄膜的長期穩定性量測

Abstract

「長期穩定性」是記錄媒體必須具備的條件之一。在磁光碟片的記錄層材 料中，DyFeCo薄膜已被證實比傳統的記錄媒體TbFeCo，能在較低的外加磁 場(bias fild)及雷射功率，達到良好的記錄效果。本論文的目的是以 Dy- FeCo薄膜與目前的磁光記錄媒體TbFeCo，做長期穩定性的比較，兩種 磁光薄膜劣化條件為85℃，85﹪相對濕度的高溫高濕之下進行加速劣化測 試。比較兩種磁光薄膜的各項性質隨時間的變化情形，可發現兩種磁光薄 膜在加速劣化的測試環境之下，(a)矯頑磁力、克爾旋轉角與磁化量，(b) 表面特性及(c)CNR皆有類似的變化；且在SiN良好的保護下，兩種磁光薄 膜均具有相當的穩定性。此結果顯示DyFeCo與TbFeCo兩種磁光薄膜的長期 穩定性相當類似，相信DyFeCo薄膜製成碟片後，也能像傳統的記錄媒體 TbFeCo一般供長期使用，成為更先進的記錄媒體。 "Long term stability" is one of the most important requirements in the recording media. It was found that DyFeCo magneto- optical (MO) thin film has almost the same recording properties as TbFe- Co, but at lower bias field and laser power. We compare the long term stabilities of DyFeCo and TbFeCo by acclerating test in the environment of 85℃ and 85﹪ reletive humidity (RH). We find th- at (a) coercivities, Kerr angles and magnetizations, (b) surface properties, and (c) CNR of these two thin films are almost the s- ame in the accelerated testing. Both of the two MO thin films are very stable under the protecting of the dielectric layer- SiN. T- he above experimental results indicate that a MO disk with DyFeCo active layer has a similar long term stability as TbFeCo thin fi- lm and therefore has the potential to become an advanced recordi- ng medium.