Compositing soft and hard materials is a promising method to decrease the coercivity of L10 FePt, which is considered to be a suitable material for bit-patterned media. This paper reports the simulation of three model...Compositing soft and hard materials is a promising method to decrease the coercivity of L10 FePt, which is considered to be a suitable material for bit-patterned media. This paper reports the simulation of three models of FeCo/L10 FePt exchange-coupled composite particles for bit patterned media by the OOMMF micromagnetic simulation software： the enclosed model, the side-enclosed model, and the top-covered model. All of them have the same volumes of the soft and hard parts but different shapes. Simulation results show that the switching fields for the three models can be reduced to about 10 kOe （1 Oe = 79.5775 A/m） and the factor gain can be improved to 1.4 when the interface exchange coefficient has a proper value. Compared to the other models, the enclosed model has a wider range of interface exchange coefficient values, in which a low switching field and high gain can be obtained. The dependence of the switching fields on the angle of the applied field shows that none of the three models are easily affected by the stray field of a magnetic head.展开更多
Nanocrystalline Nd 8.5 Fe 75 Co 5Cu 1Zr 3Nb 1B 6.5 ribbons were prepared by melt spun (18 m·s -1 ) and subsequent heat treatment (670 ℃/4 min). Excellent magnetic properties of the bonded m...Nanocrystalline Nd 8.5 Fe 75 Co 5Cu 1Zr 3Nb 1B 6.5 ribbons were prepared by melt spun (18 m·s -1 ) and subsequent heat treatment (670 ℃/4 min). Excellent magnetic properties of the bonded magnet were achieved as follows: B r=0.68 T (6 8 kGs), J H c=620.3 kA·m -1 (7.8 kOe), ( BH ) max =74 kJ·m -3 (9 3 MGOe). The results of TEM photomicrographs confirm that the appearance of α Fe phase is earlier than that of Nd 2Fe 14 B phase during crystallization process. The addition of Cu and Zr elements shows to be advantageous to the improvement of an intrinsic coercivity and squareness of hysteresis loop, as well as energy product.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 61003041,51171086,and 61272076)the Fundamental Research Funds for the Central Universities (Grant No. lzujbky-2010-81)
文摘Compositing soft and hard materials is a promising method to decrease the coercivity of L10 FePt, which is considered to be a suitable material for bit-patterned media. This paper reports the simulation of three models of FeCo/L10 FePt exchange-coupled composite particles for bit patterned media by the OOMMF micromagnetic simulation software： the enclosed model, the side-enclosed model, and the top-covered model. All of them have the same volumes of the soft and hard parts but different shapes. Simulation results show that the switching fields for the three models can be reduced to about 10 kOe （1 Oe = 79.5775 A/m） and the factor gain can be improved to 1.4 when the interface exchange coefficient has a proper value. Compared to the other models, the enclosed model has a wider range of interface exchange coefficient values, in which a low switching field and high gain can be obtained. The dependence of the switching fields on the angle of the applied field shows that none of the three models are easily affected by the stray field of a magnetic head.
文摘Nanocrystalline Nd 8.5 Fe 75 Co 5Cu 1Zr 3Nb 1B 6.5 ribbons were prepared by melt spun (18 m·s -1 ) and subsequent heat treatment (670 ℃/4 min). Excellent magnetic properties of the bonded magnet were achieved as follows: B r=0.68 T (6 8 kGs), J H c=620.3 kA·m -1 (7.8 kOe), ( BH ) max =74 kJ·m -3 (9 3 MGOe). The results of TEM photomicrographs confirm that the appearance of α Fe phase is earlier than that of Nd 2Fe 14 B phase during crystallization process. The addition of Cu and Zr elements shows to be advantageous to the improvement of an intrinsic coercivity and squareness of hysteresis loop, as well as energy product.
