Structural, Magnetic, and Magnetostriction Properties of Flexible, Nanocrystalline CoFe₂O₄ Films Made by Chemical Processing

Abstract

We report on the simple, single-step, and cost-effective fabrication, characterization, and performance evaluation of cobalt ferrite (CoFe2O4; CFO) nanocrystalline (NC) thin films on a flexible mica substrate. The chemical solution-based drop-casting method employed to fabricate crystalline CFO films and their characterization was performed by studying the phase formation, surface morphology, and magnetic parameters, while sensor applicability was evaluated using combined magnetic and magnetostrictive properties. X-ray diffraction (XRD) indicates the single-phase and nanocrystalline nature of CFO films, where the crystallite size is ∼60 nm. The optimum conditions employed resulted in CFO NC films with surface particles exhibiting a spherical shape morphology with a homogeneous size distribution, as revealed by scanning electron microscopy analyses. Raman spectroscopic characterization of the chemical bonding indicates all of the active bands that are characteristic of the ferrite phase confirm the spinel structure, which is in agreement with XRD studies. The saturation magnetization (M S) and coercivity (H C), which are extracted from the field-dependent magnetization data, of CFO NC films were found to be 15.8 emu/g and 1.6 kOe, respectively, while the first-order magnetocrystalline anisotropy constant K 1 was ∼1.07 × 106 erg/cm3. The magnetostriction strain curve indicates that the CFO NC films exhibit a strain value of ∼86 ppm at an applied magnetic field of 8 kOe, indicating their suitability for flexible sensor devices.

Effect of Ni2+and Co2+ substitution on the characteristics of the strontium aluminum hexaferrite (SrAl2Fe10O19)

“…6c) moment in strontium hexaferrite structure. According to previously reported literature, diamagnetic Al 3+ ion replaces paramagnetic Fe 3+ ion from 2a, 12k, 4f2 and 4f1 crystallographic sites of the structure [26]. It decreases the imbalanced upward spin that results in magnetic saturation reduction, and it is also in accordance with the previous work [27].…”

Exploring the structural, morphological, and multiferroic properties of Al3+ modified (1-x) BCZT-(x) CFO ceramic composites

“…This coupling can even be enhanced if the strain sensitivity of magnetostrictive or piezoelectric systems can be enhanced in some way such as by doping these with foreign atoms. Many extrinsic ME systems have been developed BaTiO 3 (BTO) and CoFe 2 O 4 (CFO).. CFO has a high magnetostrictive coefficient i.e., it has a high sensitivity to strain at room temperature which is known to be around (−1.33 × 10 -9 m A −1 ) [8]. To improve the piezoelectric property of BTO, a BaTiO 3 (BT) -based solid solution, (1-x)Ba(Zr 0.2 Ti 0.8 )O 3 -(x)(Ba 0.7 Ca 0.3 )TiO 3 (BCZT), has attracted considerable attention (piezoelectric d 33 ≈ 600 pC/N) at room temperature.…”

Effect of High-Anisotropic Co2+ Substitution for Ni2+ on the Structural, Magnetic, and Magnetostrictive Properties of NiFe2O4: Implications for Sensor Applications

“…Magnetostriction, in which the physical dimensions of magnetic materials change when a magnetic field is applied, is of great relevance for the development of cutting-edge sensors for automotive and energy technology. − Magnetostriction often involves a reversible energy exchange between the mechanical form and the magnetic form. In reality, magnetostrictive materials can be used in numerous industrial applications, particularly in sensors and actuators, because of their capacity to convert a precise amount of energy from one form to another. − As a result, currently, there is an enormous interest in one particular group or family of functional materials that exhibit magnetostriction and are called magnetostrictive smart materials (MSMs). ,,,− Due to their magnetoelastic properties, these MSMs are also widely used in a variety of technological applications, such as stress sensors, actuators, magnetostrictive filters, controlled fuel injection systems, sensors, sonar transducer systems, etc. Alloy-based MSMs, such as Terfenol-D and Galfenol, exhibit exceptional magnetostriction strain (λ) but only in the single-crystal form.…”