Magnetic interactions in anisotropic Nd-Dy-Fe-Co-B/α-Fe multilayer magnets

Abstract

The magnetic properties and the possible interaction mechanisms of anisotropic soft- and hard-magnetic multilayers have been investigated by altering the thickness of different kinds of spacer layers. The metal Ta and the insulating oxides MgO, Cr2O3 have been chosen as spacer layers to investigate the characteristics of the interactions between soft- and hard-magnetic layers in the anisotropic Nd-Dy-Fe-Co-B/α-Fe multilayer system. The dipolar and exchange interaction between hard and soft phases are evaluated with the help of the first order reversal curve method. The onset of the nucleation field and the magnetization reversal by domain wall movement are also evident from the first-order-reversal-curve measurements. Reversible/irreversible distributions reveal the natures of the soft- and hard-magnetic components. Incoherent switching fields are observed and the calculations show the semiquantitative contributions of hard and soft components to the system. An antiferromagnetic spacer layer will weaken the interaction between ferromagnetic layers and the effective interaction length decreases. As a consequence, the dipolar magnetostatic interaction may play an important role in the long-range interaction in anisotropic multilayer magnets.

Coercivity Mechanism and Magnetization Reversal in Anisotropic Ce-(Y)-Pr-Fe-B Films

“…Figure 8 b shows the distribution curves of the reversible and irreversible parts separated from the FORCs data. The separation of the reversible and irreversible processes has been performed near the descending branch of the major loop by monitoring the magnetization change versus in the original FORC [ 39 ]. In mathematical form, the reversible/irreversible parts are represented by the following formulas: …”

Anisotropic nanocomposite soft/hard multilayer magnets

“…[3,30] Thus, it is very important to make clear the mechanism of the long-range interactions between the hard-and soft-magnetic layers. Dai et al [31] analyzed the interactions mechanism by using the first-order-reversal-curves (FORCs) distributions and discussed the dependence of the mean interaction on the distance between soft-and hard-magnetic layers.…”

“…[16,22] Applied field/kOe Applied field/kOe 10 nm) (t MgO = 0 nm, 2 nm, 60 nm, 70 nm, and 100 nm). [31] The OOP demagnetization curves of multilayers with Ta and Cr 2 O 3 spacer layers are presented in Figs. 13(a) and 13(b), respectively.…”

Magnetic-Property Assessment on Dy–Nd–Fe–B Permanent Magnet by Thermodynamic Calculation and Micromagnetic Simulation

“…The compositional design can also be performed by blending precursor powders with the different grain sizes and chemical compositions of Dy alloy powders, resulting in homogeneous HRE distribution [ 15 ]. Another available method to design the microstructures in permanent magnets is achieved by growing the materials layer by layer using the vacuum sputtering system [ 16 ]. All these processes experience a complex thermodynamic evolution.…”