Of Smco Rare Earth Permanent Magnet Thin Films And The Coercivity Mechanism Study

The Sm(Co,Cu,Fe,Zr)Z thin films have been investigated extensively for its high permanent properties. In this thesis, the coercivity mechanism of the Sm(Co,Cu,Fe,Zr)Z thin films have been studied theoretically and the influences of the fabrication process on the coercivity have been studied experimentally.Based on the micromagnetic model of the Sm(CoCuFeZr)Z thin films presented in this thesis, the pining field has been computed with different physical parameters of the cell boundary phase. The results show that the pining field increases with the increasing of the thickness of the cell boundary phase and decrease with the further increasing of the thickness of the cell boundary phase. Then high pinning field can be obtained with the appropriate thickness of the cell boundary phase. And the Sm(CoCuFeZr)Z thin films with lower magnetocrystalline anisotropy constant of cell boundary phase will have a higher coercivity.The Sm(Co,Cu,Fe,Zr)Z thin films were prepared by DC magnetron sputtering on the Si substrate with Cr underlayer, and annealed in vacuum later. Firstly the dependences of the Ar pressure on the compositions of the thin films have been studied. Then the influences of common heat treatments and two-steps heat treatments on the coercivity of the Sm(Co,Cu,Fe,Zr)Z thin films have been investigated systematically. It is observed that the SmCo5 phase appears when the annealing temperature is lower than 700℃. Both the SmCo5 phase and the Sm2Co17 phase appear while the annealing temperature is higher than 700℃. The texture of the thin films is influenced by the annealing temperature remarkably. While the thin films are annealed at lower temperature, the C axis of the permanent phase tends to be perpendicular to the thin films plane, which results in the lower coercivity of the thin films. While the thin films are annealed at higher temperature, the C axis of the permanent phase tends to lie in the thin films plane, which results in the higher coercivity of the thin films. It has been found that a preferable orientation can be obtained while both the SmCo5 phase and the Sm2Co17 phase have deposited plenty in the two-steps heat treatment. Then the coercivity of the Sm(Co,Cu,Fe,Zr)Z thin film can be improved remarkably by the...