Perpendicular Coercivity Development in Tetragonally Distorted FeCo Films Due to Chromium Addition

IF 1.9 3区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

IEEE Transactions on Magnetics Pub Date : 2026-10-01 Epub Date: 2026-04-29 DOI:10.1109/TMAG.2026.3688201

Takashi Hasegawa;Tsubasa Satou;Jiaxiang Liu

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引用次数: 0

Abstract

FeCo exhibits the highest saturation magnetization among all transition metal alloys. Development of its coercivity is expected to result in superior permanent magnet properties. However, because typical FeCo possesses a body-centered cubic structure, its uniaxial magnetic anisotropy (

$K_{\mathrm{u}}$

) is extremely low; consequently, high coercivity (

$H_{\mathrm{c}}$

) is not achieved even in a granular state with fine particles. The epitaxial growth of FeCo on a buffer layer, whose lattice constant is smaller than that of FeCo (such as Rh), reportedly induces a body-centered tetragonal (bct) structure owing to lattice mismatch, resulting in high

$K_{\mathrm{u}}$

. In addition, Cr-added FeCo segregates into Cr-poor ferromagnetic and Cr-rich nonmagnetic phases. In this study, the combined effects of the bet formation and two-phase segregation induced by Cr additions were examined by depositing

$\mathrm{Fe}-\mathrm{Co}-\mathrm{Cr}$

on a Rh buffer layer. FeCo film with

$30 \mathrm{at} . \%$

added Cr achieved a high

$K_{\mathrm{u}}$

of approximately

$4 \times 10^5 \mathrm{~J} / \mathrm{m}^3$

and high coercivity of

$\mu_0 H_{\mathrm{c}} \approx 0.5 \mathrm{~T}$

. The addition of Cr promoted phase separation, producing a granular microstructure of ferromagnetic nanoparticles embedded in a nonmagnetic matrix, and contributed to the enhanced coercivity. On the contrary, films deposited on amorphous SiO2 exhibited a significantly lower coercivity of 0.04 T, dominated by shape anisotropy.

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铬对四向变形FeCo薄膜垂直矫顽力的影响

在所有过渡金属合金中，FeCo具有最高的饱和磁化强度。其矫顽力的发展有望产生优异的永磁体性能。然而，由于典型的FeCo具有体心立方结构，其单轴磁各向异性( $K_{\mathrm{u}}$ )极低；因此，高矫顽力( $H_{\mathrm{c}}$ )即使在具有细颗粒的颗粒状态下也无法实现。FeCo在晶格常数小于FeCo（如Rh）的缓冲层上外延生长，由于晶格不匹配，导致体心四边形（bct）结构，从而导致高 $K_{\mathrm{u}}$ 。添加cr的FeCo析出贫cr铁磁相和富cr非磁相。在本研究中，通过沉积的方法研究了Cr的加入对bet形成和两相偏析的综合影响 $\mathrm{Fe}-\mathrm{Co}-\mathrm{Cr}$ 在Rh缓冲层上。FeCo薄膜 $30 \mathrm{at} . \%$ 添加铬达到新高 $K_{\mathrm{u}}$ 大约 $4 \times 10^5 \mathrm{~J} / \mathrm{m}^3$ 和高矫顽力 $\mu_0 H_{\mathrm{c}} \approx 0.5 \mathrm{~T}$ 。Cr的加入促进了相分离，形成了嵌套在非磁性基体中的铁磁性纳米颗粒结构，并提高了矫顽力。相反，非晶SiO2薄膜的矫顽力明显较低，为0.04 T，主要受形状各向异性的影响。

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 Transactions on Magnetics 工程技术-工程：电子与电气

CiteScore

4.00

自引率

14.30%

发文量

565

审稿时长

4.1 months

期刊介绍： Science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage. The IEEE Transactions on Magnetics publishes scholarly articles of archival value as well as tutorial expositions and critical reviews of classical subjects and topics of current interest.