The role of shell thickness on the exchange spring mechanism of cobalt ferrite/iron cobalt magnetic nanocomposites

详细信息    查看全文

• 作者：Rohollah Safi ; Ali Ghasemi ; ^{ali13912001@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; Reza Shoja-Razavi
• 关键词：Nanocomposite ; Core-shell ; Maximum energy product ; Exchange coupling
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：617-624
• 全文大小：1875 K

文摘

CoFe₂O₄/FeCo hard/soft core-shell system with different shell thickness was obtained by precise control of surface treatment conditions of the CoFe₂O₄ nanoparticles under reduced condition. CoFe₂O₄ nanoparticles were subjected to surface reduction treatment for various period of times (10, 15, 20, 25, and 30 min) at 550 °C in order to optimize the thickness of FeCo soft shell. The phase evolution, morphology, coercivity and magnetization of the nanocomposites were examined by X-ray diffraction, electron diffraction pattern, transmission electron microscope, and vibrating sample magnetometer. The single-phase-like hysteresis loops and Henkel plot reflect the existence of the exchange coupling phenomenon in the core-shell nanocomposite. The enhancement of maximum energy product, (BH)_max, by 50% with respect to the pure CoFe₂O₄ nanoparticles is obtained for a sample treated at 20 min.