Strategy of preparing SmCo based films with high coercivity and remanence ratio achieved by temperature and chemical optimization  

作　　者：Yansong Gong Zhaoguo Qiu Sizhe Liang Xinrui Zheng Hongxia Meng Zhigang Zheng Deyang Chen Shengfu Yuan Weixing Xia Dechang Zeng J.P.Liu 

机构地区：[1]School of Materials Science and Engineering,South China University of Technology,Guangzhou,510640,China [2]Zhongshan R&D Center for Materials Surface and Thin Films Technology of the South China University of Technology,Gent Materials Surface Technology(Guangdong)Co.,Ltd.,Zhongshan,528437,China [3]Institute for Advanced Materials,South China Academy of Advanced Optoelectronics,South China Normal University,Guangzhou,510006,China [4]Yangjiang Branch,Guangdong Laboratory Materials Science and Technology Yangjiang Advanced Alloys Laboratory,Yangjiang,529500,China [5]Laboratory of Rare-Earth Magnetic Functional Materials,Ningbo Institute of Material Technology and Engineering,Chinese Academy of Sciences,Ningbo,315201,China [6]Department of Physics,University of Texas at Arlington,Arlington,TX76019,USA

出　　处：《Journal of Rare Earths》2024年第7期1289-1297,I0004,共10页稀土学报（英文版）

基　　金：Project supported by the National Key R&D Program of China(2022YFB3505700,2022YFB3807900);National Natural Science Foundation of China(51901079);R&D(Research and Development)Plan in Key Areas of Guangdong Province(SDZX2021002,212021032611700001);Natural Science Foundation of Guangdong Province(2020A1515010736,2021A1515010451);the Guangzhou Municipal Science and Technology Program(202007020008)。

摘　　要：SmCo based films with excellent intrinsic magnetic properties have promising applications in micro-electro-mechanical system(MEMS).However,due to the complexity of phase composition and uncontrollable crystallization degree of SmCo hard magnetic phase in the film,both the coercivity(Hc)and remanence(Mr)of films are difficult to enhance simultaneously.In this paper,SmCo based films were deposited with a Cr underlayer and capping layer on single crystal Si substrates via magnetron sputtering process.The effects of annealing parameters and Sm/Co atomic ratio on the phase structure and coercivity of films are discussed.By adjusting the Sm/Co atomic ratio from 1:5 to 1:4,Co soft magnetic phase disappears and the single phase SmCo5 is obtained,leading to the increase of coercivity of the films from 30 to 34 kOe.The influence of deposition temperature and Cu doping on magnetic properties of SmCo based films was investigated.When the deposition temperature increases from room temperature to 250℃,the coercivity will further increase from 34 to 51 kOe.However,a severe kink is observed in the demagnetization curves due to the poor exchanged coupling.An analysis of transmission electron microscopy(TEM)confirms that the average size of non-hard magnetic amorphous phase exceeds the effective exchanged coupling length of SmCo5,which contributes to the decoupling and low remanence ratio.Therefore,doping Cu and applying a post-annealing process can significantly improve the crystallization degree of the films.Both the coercivity and the remanence ratio of the demagnetization curves are greatly enhanced.We propose a plausible strategy to prepare the SmCo based films with high coercivity and remanence ratio by temperature and chemical optimization,which can be utilized in high performed MEMS devices.

关 键 词：Rare earths SmCo based films Phase composition Crystallization conditions COERCIVITY Remanence ratio 

分 类 号：TB383.2[一般工业技术—材料科学与工程]