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Directional Magnetization Reversal Enables Ultrahigh Energy Density in Gradient Nanostructures
Author(s) -
Lou Li,
Li Yuqing,
Li Xiaohong,
Li Hailing,
Li Wei,
Hua Yingxin,
Xia Weixing,
Zhao Zhihe,
Zhang Haitian,
Yue Ming,
Zhang Xiangyi
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202102800
Subject(s) - materials science , magnetization , condensed matter physics , coercivity , micromagnetics , magnetization reversal , ferromagnetism , isotropy , remanence , magnet , stoner–wohlfarth model , magnetic anisotropy , magnetic field , optics , physics , quantum mechanics
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 Nd 2 Fe 14 B/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.