Phase Formation Mechanism and Anomalous Magnetic Variation of High-Performance La-Co-Doped Strontium Ferrites

Pengbo Fu; Zhenhuan Li; Fang Wang; Munan Yang; Lulu Liu; Licheng Wang; Huayang Gong; Jian Zhang; Baogen Shen

doi:10.3390/ma18020323

Phase Formation Mechanism and Anomalous Magnetic Variation of High-Performance La-Co-Doped Strontium Ferrites

Materials (Basel). 2025 Jan 13;18(2):323. doi: 10.3390/ma18020323.

Authors

Pengbo Fu^{1

2}, Zhenhuan Li², Fang Wang³, Munan Yang¹, Lulu Liu², Licheng Wang², Huayang Gong², Jian Zhang², Baogen Shen²

Affiliations

¹ Faculty of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China.
² Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
³ School of Materials and Chemical Engineering, Ningbo University of Technology, Ningbo 315211, China.

PMID: 39859794
DOI: 10.3390/ma18020323

Abstract

La-Co-doped ferrite is widely used due to its excellent magnetic properties, but the mechanisms of La-Co doping on its phase formation and magnetic properties remain unclear. This study clarifies the phase formation mechanisms and reveals that La-Co doping reduces the formation temperatures of the intermediate phase SrFeO_3-x and thus the final SrFe₁₂O₁₉ phase. This promotes complete formation of SrFe₁₂O₁₉, enhancing saturation magnetization. The unexpected change in coercivity after La-Co doping contradicts the variation in the determined magnetocrystalline anisotropy field. We identify that it arises from the La-Co doping lowering the formation temperature of SrFe₁₂O₁₉, leading to excessive particle growth.

Keywords: La-Co doping; magnetic properties; permanent strontium ferrite; phase formation mechanisms; ultrapure magnetite concentrate.