Physical mechanism of perpendicular magnetic anisotropy of CoFeB thin film
| Autor: | Yen-Hsun Chen, 陳彥勲 |
|---|---|
| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 We used the structure of Sub/Ta (5)/Co20Fe60B20 (X)/MgO (1)/Ta (5) (parenthetical units are in nm) to investigate physical mechanism of perpendicular magnetic anisotropy (PMA) in CoFeB ultrathin films. The samples were annealed at temperature ranging from 200 °C to 350 °C after deposition, and their magnetic properties were measured by alternating gradient magnetometer (AGM). In order to have a deeper insight into the relationship between the film thickness and PMA, we used the ferromagnetic resonance (FMR), the x-ray absorption spectroscopy (XAS) and the x-ray magnetic circular dichroism (XMCD) to characterize the ratio of spin angular momentum and orbital angular momentum (mspin/morb). The results show that the PMA of CoFeB films are sensitive to the film thickness and annealing temperature. The PMA constant (Ku) increases with the annealing temperature. Moreover, results by comparing the relationships of mspin/morb with annealed temperature among CoFeB, Co and Fe, we found that CoFeB and Fe have very similar trends. Thus the possible physical mechanism of perpendicular magnetic anisotropy is strongly associated with Fe element. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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