Modeling hysteresis curves of anisotropic SmCoFeCuZr magnets

• Published in: Journal of magnetism and magnetic materials 2013-02, Vol.328, p.53-57
• Main Authors: Sampaio da Silva, Fernanda A., Castro, Nicolau A., de Campos, Marcos F.
• Format: Article
• Language: English
• Subjects: Alignment; Anisotropy; Coercivity; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Domain effects, magnetization curves, and hysteresis; Exact sciences and technology; Grains; Hydroxyapatite; Hysteresis; Magnet; Magnetic properties and materials; Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects; Magnets; Permanent magnets; Physics; SmCo; Studies of specific magnetic materials; Surface layer; Texture
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2012.09.048

The hysteresis curves at room temperature and at 630K of an anisotropic magnet were successfully modeled with the Stoner–Wohlfarth Callen-Liu-Cullen (SW-CLC) model. This implies that coherent rotation of domains is the reversal mechanism in this magnet. The chemical composition of the evaluated magnet is Sm(CobalFe0.06Cu0.108Zr0.03)7.2. The anisotropy field HA was estimated with the model, resulting μ0HA=7.1T at the room temperature, and 2.9T at 630K. For this sample, the CLC interaction parameter (1/d) is very low (near zero) and, thus, the nanocrystalline 2:17 grains are well “magnetically decoupled”. The texture analysis using Schulz Pole figure data indicated Mr/Ms ratio=0.96, and this means that the magnet is very well aligned. The excellent alignment of the grains is one of the reasons for the high coercivity of this sample (∼4T at room temperature). ► The Stoner–Wohlfarth model can describe the hysteresis curves of anisotropic Sm2Co17 magnets, since the Callen-Liu-Cullen correction is applied. ► The anisotropy field of the hard magnetic phase Sm2Co17 can be estimated from the hysteresis curves of anisotropic magnets, since the crystallographic texture is known. ► It is presented a texture study of commercial sintered Sm2Co17 type magnets. ► The texture data can be used for evaluation of the squareness of the 2nd quadrant of the hysteresis curve, in Sm2Co17 hard coercivity magnets.