Magnetic properties of TbCo/FePt bilayer films

Full text: Introduction: In this work, we fabricate the FM/FI film (FM=ferromagnetic and FI=ferrimagnetic) of TbCo with the FePt magnetic underlayer to investigate the magnetic properties of TbCo/FePt bilayer films. It is found that coercivity of the TbCo/FePt bilayer film is larger than that of single layer CoTb or FePt film. Experiment: We fabricated the film of Si/CoTb/Si3N4 and Si/FePt/CoTb/Si3N4, respectively. Results and Discussion: The film is an amorphous structure. Fig. 1 is found that the out-plane squareness is bigger than that of in-plane for Si/CoTb/Si3N4. And the in-plane squareness is larger than that of out-plane for Si/FePt. Fig. 2 shows the hysteresis loop of bi-layer Si/FePt/CoTb/Si3N4 films. The out-plane coercivity of bi-layer Si/FePt/CoTb/Si3N4 films is about 2.8 kOe which is almost the same as that of Si/CoTb/Si3N4. The in-plane coercivity is about 3 kOe which is larger than that of Si/FePt. This indicates that the in-plane magnetic anisotropy will appear when the FePt under layer is introduced at 450?. In this report, we will discuss the magnetic properties of the bi-layer Si/FePt/CoTb/Si3N4 films when FePt under layer is deposited at different temperatures. Fig.1.The hysteresis loop of Si/CoTb/Si3N4. Fig.2.The hysteresis loop of Si/FePt/CoTb/Si3N4. References [1] S. Miyanishi, K. Kojima, J. Sato, K. Takayama, H. Fuji, A. Takahashi, and K. Ohta, J. Appl. Phys., 93, 7801 (2003). [2] Pyungwoo Jang, Sooyoul Hong, and Jongryul Kim, J. Appl. Phys., 93, 7741 (2003)