The crystal structures of sintered pure Co and Co

A. Powders: solid state reaction; C. Magnetic properties; D. Ferrites; D. Spinels; E. Functional applications
1. Introduction
Spinel type cobalt ferrite (CoFe2O4) has been extensively studied and utilized because it has good electromagnetic properties, high magnetocrystalline anisotropy, excellent chemical stability, good mechanical properties, and excellent corrosion resistance, with the added benefit of easy processability [1] and [2]. In addition, it exhibits a large magnetomechanical effect or high strain sensitivity, which offers prospects for magnetic Potassium Canrenoate and/or actuator applications [3]. Cobalt ferrite is a suitable magnetic material for those purposes. However, it is necessary and desirable to enhance the sensitivity of the magnetostrictive strain to an applied magnetic field (i.e., the strain derivative) and decrease the magnetomechanical hysteresis, which would improve the linear response of a future magnetostrictive sensing device [4] and [5].
The magnetic, magnetostrictive, and electrical properties of the spinel type ferrites are in general affected by the preparation method, microstructure changes, chemical composition, and other factors. Substituting cations for cobalt ferrites appear to hold the promise of modifying their magnetostriction amplitude and enhancing strain sensitivity, as well as providing the possibility of extending the applications of magnetostrictive smart materials [6]. Previous reports have shown that substitution of cations (e.g., Al, Cr, Mn, Zn, Ga, and Ge) for some Fe ions in Co-ferrites could be used to adjust the Curie temperature and reduce the magnetomechanical hysteresis, while enhancing the strain sensitivity and maintaining a sufficient amplitude of magnetostriction [7] and [8].