Giant magnetoelastic properties in Ce-substituted and magnetic field processed cobalt ferrite

Abstract

The magnetoelastic properties of Ce-doped cobalt-ferrite Co1+xCexFe2-2xO4 (0 ≤ x ≤ 0.04) synthesized by magnetic-field assisted compaction dramatically improved in comparison to the conventionally compacted undoped cobalt ferrite. The peak magnetostriction (λp) increased by ∼130%, and the strain sensitivity (dλ/dH)max gained by ∼600%. Ce-doping up to x = 0.03 in cobalt ferrite constituted the cubic spinel phase. The lattice parameter (a) increased with the increase in Ce content up to x = 0.03 and subsequently decreased at x = 0.04, while the nature of compaction had an insignificant impact on a. The average grain size ranged from ∼10 to 25 μm in doped cobalt–ferrites. The magnetic saturation (MS) decreased linearly with the dopant content, and the magnetic-field-assisted compacted doped-cobalt-ferrites exhibited lower coercivity (HC) compared to the conventionally compacted counterparts. The undoped and doped cobalt ferrites synthesized by magnetic-field-assisted compaction exhibited significantly higher λp (a two-fold increase) compared to the conventionally compacted counterparts. For both conventional and magnetic-field-assisted compaction, λp and (dλ/dH)max gradually increased with the increase in the Ce-content from x = 0 to x = 0.03, and subsequently decreased at x = 0.04. The (dλ/dH)max for the magnetic field-assisted compacted Ce-doped cobalt-ferrite at Ce-content x = 0.03 increased to ∼5.5 × 10−9 m/A compared to 0.8 × 10−9 m/A for conventionally compacted undoped cobalt ferrite.