Directional Magnetization Reversal Enables Ultrahigh Energy Density in Gradient Nanostructures

Abstract

High‐performance ferromagnetic materials are essential for energy conversion and electronic devices. However, the random and nonuniform magnetization reversal in ferromagnetics limits their performance that can be achieved. Here, through both micromagnetism simulations and experiments, a directional magnetization reversal that initiates first from large grains toward smaller ones is discovered by engineering Nd2Fe14B/α‐Fe gradient nanostructures. Such directional magnetization reversal enables a rare combination of high magnetization and large coercivity, thus leading to a record‐high energy density (26 MG Oe) for isotropic permanent magnetic materials, which is ≈50% higher than that of its gradient‐free counterpart. The unusual magnetization reversal originates from an ordered arrangement of grain sizes in the gradient material, where the large grains have a lower reversal field than that of the smaller ones. These findings open up new opportunities for developing high‐performance magnetic materials.

Perspective and Prospects for Ordered Functional Materials

“…a) Reproduced with permission. [ 17 ] Copyright 2021, John Wiley and Sons. Reproduced with permission.…”

Effect of Strain Rate on Microstructure and Mechanical Properties of Electroplastic Rolled ZrTi Alloy

“…The quantitative analysis of XRD spectra was conducted by the Rietveld refinement method. [33][34][35][36] Tensile tests were performed on the samples with a cross-section of 2.00 mm  0.25 mm and a gauge length of 5 mm using an Instron 5948 Micro Tester at a strain rate of 10 À3 s À1 at room temperature. The tensile direction was parallel to the rolling direction of the samples.…”

Intrinsically High Magnetic Performance in Core–Shell Structural (Sm,Y)Fe12‐Based Permanent Magnets

“…The development of high-performance permanent magnets is critical for the efficiency and reliability of electric vehicles, wind power generation, industrial robots, and other emerging industries. [1][2][3][4] ThMn 12 -type SmFe 12 -based permanent magnets have been recognized as the promising one of potential candidates because of their intrinsically high temperature stability of magnetic properties. [5][6][7][8][9][10][11] However, because of the metastable enhanced pinning effect of domain walls of magnetic hardening shells.…”