Magnetization reversal and magnetic interactions in anisotropic Nd–Dy–Fe–Co–B/MgO/α-Fe disks and multilayers

Abstract

We report on a field induced domain evolutionary procedure in the anisotropic Nd-Dy-Fe-Co-B/MgO/Fe multilayers by using first-order-reversal-curves and magnetic force microscopy. Different reversal behaviors and domain sizes are found in well coupled and decoupled multilayers by changing the thickness of the spacer layer. The competition between dipolar magnetostatic energy and Zeeman energy is evaluated by in-field observation throughout nucleation and annihilation processes. In addition, lithography-patterned arrays of soft Fe disks onto a continuous Nd-Dy-Fe-Co-B hard-magnetic layer are designed. By decreasing the applied field, it is found that magnetization orientations of the Fe disk and Nd-Dy-Fe-Co-B layer are aligned parallel. In the decoupled disk, although the out-of-plane magnetization orientations are observed, the orientation of the domains in the Fe disk is random. Furthermore, it is found that a stronger anisotropy of the Nd-Dy-Fe-Co-B layer decreases the interaction length. Our results provide a new understanding of anisotropic nanocomposite magnets with long-ranged magnetic interactions.

Regulable Properties in Multicomponent Rare Earth Magnetic Particle SmxPr1–xCo5 by a Specially Designed Co Nanomatrix Precursor: Implications for Magnets with Different Application Temperatures

“…Multicomponent rare earth (RE) has been widely used in the preparation of various permanent magnets. − In Nd 2 Fe 14 B-based permanent magnets, for example, Dy or Tb was added to increase coercivity, and Ce was added to balance the utilization of different RE elements. − In SmCo 5 -based permanent magnets, the performance is limited due to their low saturation magnetization. , PrCo 5 and SmCo 5 have the same crystal structure, both of which are CaCu 5 -type hexagonal structures, but the saturation magnetization of PrCo 5 ( M s = 123.1 emu/g) is significantly higher than that of SmCo 5 ( M s = 107.2 emu/g). In contrast, the anisotropy field of PrCo 5 ( H A = 179 kOe) is much lower than that of SmCo 5 ( H A = 420 kOe). − Therefore, it is expected that SmCo 5 and PrCo 5 can be combined with appropriate composition to improve the M s of SmCo 5 compounds at the expense of moderate reduction of H A to obtain the optimal magnetic properties. , In addition, the magnets with the flexible option of properties can cope with different application requirements, especially different coercivity parameters for different operating temperatures.…”