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以微磁学理论为基础,利用OOMMF软件采用三维动力学模型模拟研究了Sm-Co/α-Fe/Sm-Co交换耦合三层膜体系的磁滞回线,并对其磁性能分别与软、硬磁层厚度的关系进行了系统的分析.研究结果表明:只有当软磁层厚度小于其临界尺寸(5 nm)时,磁滞同线近似为矩形,此时三层膜完全耦合;硬磁层的厚度对体系的磁性能也有着密切的关系,而且硬磁层的厚度对体系软磁相的临界尺寸也有着一定的影响,只有在合适的软、硬磁含量比例的情况下才能得到具有最佳磁性能的三层膜. 相似文献
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Effects of thickness and annealing condition on magnetic properties and thermal stabilities of Ta/Nd/NdFeB/Nd/Ta sandwiched films 下载免费PDF全文
Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si(100) substrates,and subsequently annealed in vacuum at different temperatures for different time.It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films.Interestingly,the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film.The high coercivity of 24.1 kOe(1 Oe = 79.5775 A/m) and remanence ratio(remanent magnetization/saturation magnetization)of 0.94 can be obtained in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed for 3 min at 1023 K.In addition,the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well.The excellent thermal stability can be achieved in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed at1023 K. 相似文献
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Martensitic transformation and giant magnetic entropy change in Ni_(42.8)Mn_(40.3)Co_(5.7)Sn_(11.2) alloy 下载免费PDF全文
The crystal structure, phase transition, and magnetocaloric effect in Ni42.8Mn40.3Co5.7Sn11.2 alloy are investigated by structure analysis and magnetic measurements. A large magnetic entropy change of 45.6 J/kg.K is obtained at 215 K under a magnetic field of 30 kOe (1 Oe = 79.5775 A.m-1). The effective refrigerant capacity of Ni42.8Mn40.3Co5.7Sn11.2 alloy reaches 72.1 J/kg under an applied field changing from 0 to 30 kOe. The external magnetic field shifts the martensitic transition temperature about 3-4 K/10 kOe towards low temperature, indicating that magnetic field can retard the phase transition to a certain extent. The origin of large magnetic entropy change is discussed in the paper. 相似文献
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Magnetoresistance and exchange bias in high Mn content melt-spun Mn_(46)Ni_(42)Sn_(11)Sb_1 alloy ribbon 下载免费PDF全文
Highly textured Heusler alloy Mn_(46)Ni_(42)Sn_(11)Sb_1 ribbons were prepared by melt spinning. The annealed high Mn content Mn46Ni42Sn11Sb1 ribbon cross-section microstructure, crystal structure, martensitic transformation(MT), and magnetoresistance(MR) properties were investigated. The MR in the annealed ribbon was assessed by the magnetic field direction perpendicular to the ribbon surface with the magnetic field up to 30 k Oe. The large negative value of 25% for MR was obtained at 244 K. The exchange bias(EB) effects of the as-spun and annealed ribbons were investigated. After annealing, the EB effects have been improved by about 25 Oe at the temperature of 50 K. The magnetizations have increased approximately by 10% more than the as-spun ribbon. 相似文献
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采用溶剂热法制备正极材料LiFePO_4,采用溶胶凝胶法制备Li_(0.5)La_(0.5)TiO_3(LLTO)粉体,并通过酒精悬浮法对LiFePO_4进行修饰,修饰量为LiFePO_4质量的1%~4%,获得了薄壁蜂窝状自组装结构的LiFePO_4上修饰有球状LLTO纳米颗粒的复合正极材料。通过进行充放电测试、交流阻抗测试及循环伏安测试,研究了不同修饰量对电池的充放电比容量、循环性能及可逆性的影响,发现当LLTO含量为3%(w/w)时,以2C和5C倍率放电相对于没有修饰LLTO的LiFePO_4的比容量分别提高29.7%和31.6%,30次循环之后,容量损失率较未改性前减小4.13%,循环伏安曲线上氧化还原峰之间的电位差仅为0.117 V,以3%的LLTO修饰改性的LiFePO_4显著提高了电池的倍率性能、循环性能和低温性能。 相似文献