SmxCo100-x /Tb29.3Co70.7及Tb29.3Co70.7/ Tb17.2Co82.8雙層熱寫磁讀記錄薄膜之研製

Abstract

本實驗以直流磁控濺鍍，於自然氧化的矽晶圓(100)基板和康寧玻璃基板上分別鍍製35 nm的SmCo以及90 nm的Tb29.3Co70.7合金薄膜當做底層，再以直流磁控濺鍍分別於SmCo及Tb29.3Co70.7薄膜上分別鍍製Tb29.3Co70.7及Tb17.2Co82.8薄膜，最後以射頻磁控濺鍍在TbCo薄膜上濺鍍一層20 nm的SiNx保護層，避免TbCo合金薄膜氧化。探討不同薄膜厚度及基板溫度對於Smx Co100-x/Tb29.3Co70.7與Tb29.3Co70.7/ Tb17.2Co82.8雙層薄膜磁性質的影響。 Tb17.2Co82.8 /Tb29.3Co70.7雙層薄膜，由於Sm14.3Co85.7為水平異向性。當Sm14.3Co85.7之Hc較TbCo小，施加反向磁場時，Hc較小的一層翻轉，受coupling影響部分Hc較大的一層也一起翻轉。造成整體Hc值反而小於Hc較大的單層。另一方面，當Sm14.3Co85.7厚度為15 nm時，其垂直膜面方向磁性質為最佳，S⊥= 0.75而Mr⊥約為200 emu/cm3。 此外，Tb29.3Co70.7（RE-rich）/Tb17.2Co82.8（TM-rich）雙層薄膜， 之記錄層Tb29.3Co70.7（RE-rich）有很大的Hc⊥值（5 kOe），而讀出層Tb17.2Co82.8（TM-rich）具有高的殘留磁化量Mr⊥=220 emu/cm3。具有可應用於熱寫磁讀記錄媒體的潛力。

DC magnetron sputtering is used to deposit 35 nm SmCo film and 90 nm Tb29.3Co70.7 on the naturally oxidized Si (100), then deposited Tb29.3Co70.7 film and Tb17.2Co82.8 film on the SmCo film and the Tb29.3Co70.7 film, respectively.. Finally, a 20 nm thickness SiNx film is deposited on the TbCo film by RF magnetron sputtering to avoid the TbCo film from oxidation. The effect of thicknesses and substrate temperatures on the magnetic properties of SmxCo100-x /Tb29.3Co70.7 and Tb29.3Co70.7/ Tb17.2Co82.8 films are investigated. During magnetic reversal process, the magnetic moments of Sm14.3Co85.7 films with small Hc⊥ value would couple with a part of magnetic moments of Tb29.3Co70.7 film with high Hc⊥ value. Therefore, the Hc⊥ value of the Sm14.3Co85.7 /Tb29.3Co70.7 bilayer layer is smaller than that of Tb29.3Co70.7 single layer. When the thickness of Sm14.3Co85.7 is about 15 nm, the S⊥ and Mr⊥ values are about 0.75 and 200 emu/cm3, respectively. For the Tb29.3Co70.7（RE-rich）/Tb17.2Co82.8（TM-rich）bilayer films, because the recording layer of Tb29.3Co70.7（RE-rich） has large Hc⊥ value（about 5 kOe）and the readout layer of Tb17.2Co82.8 （TM-rich）has enough Mr⊥value (about 220 emu/cm3), it has potential to be applied on HAMR media.