Magnetic Properties of Nd-Fe-B Single Dots Fabricated Using the PLD–LIFT Method

IF 1.1 4区物理与天体物理 Q4 ENGINEERING, ELECTRICAL & ELECTRONIC

IEEE Magnetics Letters Pub Date : 2026-01-12 DOI:10.1109/LMAG.2026.3652505

K. Koike;T. Okawa;Y. Ikagawa;T. Amiya;G. Tahara;M. Itakura;T. Yasunaga;M. Nakano

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Abstract

Single-dot Nd-Fe-B micromagnets were fabricated using the pulsed laser deposition-laser-induced forward transfer (PLD–LIFT) technique, and their magnetic properties were systematically examined. Hysteresis measurements with a vibrating sample magneto meter revealed that the coercivity (H_c) was nearly independent of laser power, whereas an increased defocus rate (DF rate) enhanced H_c up to 340 kA/m. Scanning electron microscopy and cross-sectional scanning transmission electron microscopy analyses revealed that each dot comprises grains ranging from submicrometer to micrometer scale. Within these grains, an Nd₂Fe₁₄B core is encapsulated by an Fe-rich matrix containing dispersed Nd oxides. The thickness of this Fe-rich outer shell modifies the exchange pathway at the Nd₂Fe₁₄B/Fe interface, giving rise to the characteristic two-step demagnetization. Guided by these observations, a simplified Nd₂Fe₁₄B/α-Fe core–shell model was developed and evaluated through micromagnetic simulations, which successfully reproduced the stepwise reversal and clarified DF’s role in suppressing soft-phase connectivity and improving loop squareness. Collectively, these findings identify DF rate as the dominant processing parameter and provide practical guidelines for tailoring PLD–LIFT Nd-Fe-B micromagnets toward microelectromechanical systems applications.

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用PLD-LIFT法制备Nd-Fe-B单点的磁性能

采用脉冲激光沉积-激光诱导正向转移（PLD-LIFT）技术制备了单点Nd-Fe-B微磁体，并对其磁性进行了系统测试。磁滞测量表明，矫顽力（Hc）几乎与激光功率无关，而离焦率（DF率）的增加使矫顽力（Hc）提高到340 kA/m。扫描电镜和横断面扫描透射电镜分析表明，每个点由亚微米到微米尺度的颗粒组成。在这些颗粒中，Nd2Fe14B芯被含有分散的Nd氧化物的富铁基体包裹。富铁外壳的厚度改变了Nd2Fe14B/Fe界面处的交换途径，导致了典型的两步退磁。在此基础上，建立了一个简化的Nd2Fe14B/α-Fe核壳模型，并通过微磁模拟对其进行了评价，该模型成功再现了Nd2Fe14B/α-Fe核壳模型的逐步反转，阐明了DF在抑制软相连接和提高环方度方面的作用。总的来说，这些发现确定了DF率是主要的加工参数，并为针对微机电系统应用定制PLD-LIFT Nd-Fe-B微磁体提供了实用指南。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

IEEE Magnetics Letters PHYSICS, APPLIED-

CiteScore

2.40

自引率

0.00%

发文量

期刊介绍： IEEE Magnetics Letters is a peer-reviewed, archival journal covering the physics and engineering of magnetism, magnetic materials, applied magnetics, design and application of magnetic devices, bio-magnetics, magneto-electronics, and spin electronics. IEEE Magnetics Letters publishes short, scholarly articles of substantial current interest. IEEE Magnetics Letters is a hybrid Open Access (OA) journal. For a fee, authors have the option making their articles freely available to all, including non-subscribers. OA articles are identified as Open Access.