Key role in giant magnetoresistance of granular films: Single-domain ferromagnetic granules

详细信息	查看全文 | 推荐本文 |

• 作者：Changzheng Wang ; Yonghua Rong and T.Y. Hsu (Xu Zuyao)
• 关键词：Giant magnetoresistance ; Granular films ; Single-domain ferromagnetic granules
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2006
• 期刊代码：31_03048853
• 类别：ph
• 出版时间：October 2006
• 卷：305
• 期：2
• 页码：310-314
• 文件大小：197 K

摘要

The challenging problem on what kind of ferromagnetic granules plays a key role in giant magnetoresistance (GMR) was investigated. By analyzing the hysteresis curves and GMR of FeCo–Al₂O₃ films with different volume fraction of granules, we found that only the change of the fraction of single-domain granules over total ferromagnetic granules with the volume fraction of FeCo granules in FeCo–Al₂O₃ film is in agreement with that of GMR. This verifies the key role of single-domain granule in GMR. And it was also confirmed by our annealing experiments. However, the hysteresis curve of FeCo–Al₂O₃ film with low FeCo content exhibits superparamagnetic characteristic when it is measured at room temperature, which is attributed to the fact that the fraction of superparamagnetic granules is in majority.