High magnetostriction and coupling coefficient for sintered cobalt ferrite derived from superparamagnetic nanoparticles

Mohaideen, K. Khaja; Joy, P.A.

doi:10.1063/1.4745922

Cited by 64 publications

(37 citation statements)

References 19 publications

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“…3,7,8 The cation distribution is expected to affect the magnetization via cation-cation (c-c)/cation-anion-cation(c-a-c) or A-B exchange interaction, electrical conductivity, magnetic anisotropy, Curie temperature (T C ), and the magnetostriction coefficient of the material. 9,10 Cation migration can be enabled by thermal effects like annealing and quenching, 11 particle size, 12 lattice diffusion, 13 preparation condition, 2 namely, reduction reaction leading to reduction in the Fe content at B-site, 6,14,15 pressure, 16 and strain. 17,18 With increasing annealing temperature, the average particle size increases, which in turn increases the magnetization due to cation reordering.…”

Section: Introductionmentioning

confidence: 99%

Metallic magnetism and change of conductivity in the nano to bulk transition of cobalt ferrite

Arunkumar

Vanidha

Oudayakumar

et al. 2013

Journal of Applied Physics

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Articles you may be interested inThermal effect on magnetic parameters of high-coercivity cobalt ferrite J. Appl. Phys. 116, 033901 (2014); 10.1063/1.4890033Structural and ambient/sub-ambient temperature magnetic properties of Er-substituted cobalt-ferrites synthesized by sol-gel assisted auto-combustion method Variations in conductivity with particle size have been observed in cobalt ferrite, when synthesized by solgel auto-combustion method. Impedance analysis reveals metallic and semiconducting behavior at room temperature for a particle size of 6 nm and 52 nm, respectively. Upon thermal activation, metallic to semiconducting phase transition has been observed as a function of particle size and vice-versa. Grainboundary Resistance (R gb ), increased drastically with particle size (19 MX for 6 nm and 259 MX for 52 nm) at room temperature. AC conductivity and dielectric constants exhibit similar metallic to semiconducting phase transition at 6 nm and semiconducting behavior at 52 nm with temperature in the selected frequencies. Enhanced magnetic moment with an increase in the grain size along with decreased coercivity (1444 G to 1146 G) reveals transition from single domain to multi-domain. Increased inter-particle interaction is responsible for metallicity at the nano level and on the contrary semiconductivity is attributed to bulk. V C 2013 AIP Publishing LLC. [http://dx.

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Section: Introductionmentioning

confidence: 99%

Metallic magnetism and change of conductivity in the nano to bulk transition of cobalt ferrite

Arunkumar

Vanidha

Oudayakumar

et al. 2013

Journal of Applied Physics

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“…This can be done by magnetic annealing [11][12][13][14][15], magnetic-field-assisted compaction [16,17], or reaction under uniaxial pressure [18]. Another way to tune magnetostrictive properties of CoFe 2 O 4 is by substitution of the Fe atoms by Mg, Al, Ti, Mn, Ni, Cu, Zn, Ga, Zr, Nb, In, etc., or even rare-earth elements [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Magnetostriction of CoFe2O4 and Its Role in Magnetoelectric Composites

et al. 2018

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Applications of magnetostrictive materials commonly involve the use of the dynamic deformation, i.e., the piezomagnetic effect. Usually, this effect is described by the strain derivative ∂λ=∂H, which is deduced from the quasistatic magnetostrictive curve. However, the strain derivative might not be accurate to describe dynamic deformation in semihard materials as cobalt ferrite (CFO). To highlight this issue, dynamic magnetostriction measurements of cobalt ferrite are performed and compared with the strain derivative. The experiment shows that measured piezomagnetic coefficients are much lower than the strain derivative. To point out the direct application of this effect, low-frequency magnetoelectric (ME) measurements are also conducted on bilayers CFO=PbðZr; TiÞO 3 . The experimental data are compared with calculated magnetoelectric coefficients which include a measured dynamic coefficient and result in very low relative error (<5%), highlighting the relevance of using a piezomagnetic coefficient derived from dynamic magnetostriction instead of a strain derivative coefficient to model ME composites. The magnetoelectric effect is then measured for several amplitudes of the alternating field H ac , and a nonlinear response is revealed. Based on these results, a trilayer CFO/PbðZr; TiÞO 3 /CFO is made exhibiting a high magnetoelectric coefficient of 578 mV=A (approximately 460 mV=cm Oe) in an ac field of 38.2 kA=m (about 48 mT) at low frequency, which is 3 times higher than the measured value at 0.8 kA=m (approximately 1 mT). We discuss the viability of using semihard materials like cobalt ferrite for dynamic magnetostrictive applications such as the magnetoelectric effect.

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“…Introducing uniaxial anisotropy was also found to improve the longitudinal strain derivative q m 11 = dλ 11 /dH while reducing the transverse strain derivative d m 21 [12], [13]. In Figure 3, the magnetic field derivative of the magnetostrictive curves are represented in the longitudinal and transverse direction for CF-CM and CF-SPS.…”

Section: B Magnetostriction and Piezomagnetismmentioning

confidence: 96%

Enhancement of the Magnetoelectric Effect in Multiferroic CoFe₂O₄/PZT Bilayer by Induced Uniaxial Magnetic Anisotropy

et al. 2017

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In this study we have compared magnetic, magnetostrictive and piezomagnetic properties of isotropic and anisotropic cobalt ferrite pellets. The isotropic sample was prepared by the ceramic method while the sample exhibiting uniaxial anisotropy was made by reactive sintering using Spark Plasma Sintering (SPS). This technique permits to induce a magnetic anisotropy in cobalt ferrite in the direction of the applied pressure during SPS process. Sample with uniaxial anisotropy revealed a higher longitudinal magnetostriction and piezomagnetism compared to the isotropic sample, but the transversal magnetostriction and piezomagnetism were dramatically reduced. In the case of magnetoelectric layered composite, the magnetoelectric coefficient is directly related to the sum of the longitudinal and transversal piezomagnetic coefficients. These two coefficients being opposite in sign, the use of material exhibiting high longitudinal and low transversal piezomagnetic coefficient (or vice versa) in ME devices is expected to improve the ME effect. Hence, ME bilayer devices were made using isotropic and anisotropic cobalt ferrite stuck with a PZT layer. ME measurements at low frequencies revealed that bilayer with anisotropic cobalt ferrite exhibits a ME coefficient three times higher than a bilayer with isotropic cobalt ferrite. We also investigated the behavior of such composites when excited at resonant frequency.

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High magnetostriction and coupling coefficient for sintered cobalt ferrite derived from superparamagnetic nanoparticles

Cited by 64 publications

References 19 publications

Metallic magnetism and change of conductivity in the nano to bulk transition of cobalt ferrite

Metallic magnetism and change of conductivity in the nano to bulk transition of cobalt ferrite

Dynamic Magnetostriction of CoFe2O4 and Its Role in Magnetoelectric Composites

Enhancement of the Magnetoelectric Effect in Multiferroic CoFe₂O₄/PZT Bilayer by Induced Uniaxial Magnetic Anisotropy

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High magnetostriction and coupling coefficient for sintered cobalt ferrite derived from superparamagnetic nanoparticles

Cited by 64 publications

References 19 publications

Metallic magnetism and change of conductivity in the nano to bulk transition of cobalt ferrite

Metallic magnetism and change of conductivity in the nano to bulk transition of cobalt ferrite

Dynamic Magnetostriction of CoFe2O4 and Its Role in Magnetoelectric Composites

Enhancement of the Magnetoelectric Effect in Multiferroic CoFe2O4/PZT Bilayer by Induced Uniaxial Magnetic Anisotropy

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Enhancement of the Magnetoelectric Effect in Multiferroic CoFe₂O₄/PZT Bilayer by Induced Uniaxial Magnetic Anisotropy