Reversal mechanism of L10-FePt/Ni investigated by first-order-reversal-curves and x-ray magnetic circular dichroism

• Main Authors: Lee, I-Hsien, 李一憲
• Other Authors: Tseng, Yuan-Chieh
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/05372065447861393705

碩士 === 國立交通大學 === 材料科學與工程學系所 === 103 === Magnetic thin films with strong perpendicular anisotropy are intensively studied due to the increasing demand in high-density recording media. Perpendicular magnetic films with an exchange coupled composite (ECC) structure containing soft and hard layers offer the possibilities to satisfy many conflicting requirements in the world of magnetic recording. Especially, its flexibility of tuning the soft/hard layer properties plays as a versatile toolbox that provides all kinds of degree of freedom to achieve that goal. The magnetization reversal is one of the critical mechanisms determining a recording medium’s functionality, where the soft-hard layer interactions predominantly drive the whole mechanism. Characterization tools that can precisely monitor the reversal processes in various soft-hard combinations are highly desired in this field. In this study we enlisted a combination of x-ray magnetic circular dichroism (XMCD) and first order reversal curves (FORC) to explore the switching characteristics of a series of Ni/L10-FePt ECC, where XMCD probed magnetic contributions from soft/hard layers with element-specificity, while FORC provided information such as a full mapping of magnetic switching, coexistence of various magnetic natures, and the distribution of interaction field. The study points to strong sensitivity of interfacial interactions to the attendant phenomenon, such as different levels of domain-penetration from soft to hard layers by manipulating one layer through the other. By operating sophisticated switching field distribution (SFD) analyses, we further decomposed the major hysteresis loop into multiple switching components to further expound the physics behind the theme. The results open up opportunities to tailor the properties of similar systems by manipulating the soft-hard interdependency because of a deeper understanding of the subject matter.