01760nas a2200157   4500008004100000022001400041245016800055210006900223260011000292300001600402490000700418520099400425100002701419700002501446856013101471       2016                        eng d  a1463-907600aEnhancing the strain sensitivity of CoFe2O4 at low magnetic fields without affecting the magnetostriction coefficient by substitution of small amounts of Mg for Fe0 aEnhancing the strain sensitivity of CoFe2O4 at low magnetic fiel  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAPR  a10516-105270 v183 a<p>Attaining high magnetostrictive strain sensitivity (d lambda/dH) with high magnetostriction strain (lambda) is desirable for sintered polycrystalline cobalt ferrite for various applications. It is shown that substitution of a small amount of Fe3+ by Mg2+ in CoMgxFe2-xO4 (x &lt; 0.1) gives a comparable maximum magnetostriction coefficient to that of the unsubstituted counterpart, with large improvement in the strain sensitivity at relatively low magnetic fields. A large increase in the magnetostriction coefficient is obtained at low magnetic fields for the substituted compositions. The magnetostriction parameters are further enhanced by magnetic field annealing of the sintered products. The results are analyzed based on powder XRD, Raman spectroscopy, XPS and magnetic measurements and based on the results from these studies, the changes in the magnetostriction parameters are correlated with the changes in the cation distribution, magnetic anisotropy and microstructure.</p>1 aAnantharamaiah, P., N.1 aJoy, Pattayil, Alias  uhttps://library.ncl.res.in/content/enhancing-strain-sensitivity-cofe2o4-low-magnetic-fields-without-affecting-magnetostriction02433nas a2200145   4500008004100000245017200041210006900213260000800282300002700290490000700317520179100324100002702115700001602142856012902158       2017                        eng d00a Effect of size and site preference of trivalent non-magnetic metal ions (Al3+, Ga3+, In3+) substituted for Fe3+ on the magnetostrictive properties of sintered CoFe2O40 aEffect of size and site preference of trivalent nonmagnetic meta  cNOV  aArticle Number: 4350050 v503 aThe influence of size and crystallographic site preference of three non-magnetic isovalent metal ions of larger (In3+), comparable (Ga3+) and smaller (Al3+) sizes, substituted for Fe3+ in the spinel lattice of CoFe2O4 on its magnetostrictive properties is compared. For the different compositions in CoFe2-xMxO4 (M = In3+, Ga3+, Al3+ and 0 <= x <= 0.3), significant changes in the structural and magnetic parameters are observed with the degree of substitution, due to the size and site preferences. Magnetic and Raman spectral studies revealed that Al3+ is substituted for Fe3+ at both octahedral and tetrahedral sites for all compositions, whereas In3+ and Ga3+ are substituted for Fe3+ at the tetrahedral site only for x <= 0.2 and partly at the octahedral site for x > 0.2. Regardless of the differences in the ionic size, site preference and the magnetic properties, compositions in all three series with x = 0.1 showed almost equal magnitude of maximum magnetostriction (lambda(max) = similar to 230 ppm), marginally higher than that of x = 0 (217 ppm). However, at higher substituted compositions, lambda(max) is decreased with x, but the decrease is much faster for the Al-substituted compositions. The maximum strain sensitivity, [d lambda/dH](max), is also found to be comparable for all three compositions. The comparable magnetostriction characteristics and high strain at low magnetic fields for different substituted compositions at low levels of substitution are attributed to the local structural distortions associated with the inhomogeneous distribution of the substituted ions in the spinel ferrite lattice. The studies suggest ways to optimise the magnetostriction properties of properly substituted sintered cobalt ferrite for applications in sensors and actuators.1 aAnantharamaiah, P., N.1 aJoy, P., A.  uhttps://library.ncl.res.in/content/effect-size-and-site-preference-trivalent-non-magnetic-metal-ions-al3-ga3-in3-substituted01898nas a2200145   4500008004100000245009300041210006900134260000800203300001200211490000800223520137300231100002701604700001601631856010501647       2019                        eng d00aEffect of co-substitution of Co2+ and V5+ for Fe3+ on the magnetic properties of CoFe2O40 aEffect of cosubstitution of Co2 and V5 for Fe3 on the magnetic p  cFEB  a107-1130 v5543 aDifferent chemical compositions in Co1+2xVxFe2-3xO4 (0 ≤ x ≤ 0.1) have been synthesized by the conventional solid-state reaction method and processed under identical conditions. The materials are investigated to assess the impact of change in the oxidation states of metal ions on structural and magnetic properties of cobalt ferrite. Rietveld refinement of the X-ray diffraction patterns revealed a single phase nature of all compositions with cubic spinel structure. The cubic lattice parameter was found to decrease non-linearly from 8.393 Å for x = 0 to 8.377 Å for x = 0.1, due to the effect of ionic size and valency of the substituted metal ions. Sintered co-substituted compositions exhibited smaller grains against unsubstituted counterpart, due to low melting point of raw material V2O5. Strong experimental evidence of V substitution for Fe at the tetrahedral sites of the spinel ferrite has been extracted from the Raman spectral analysis. Saturation magnetization (Ms) was observed to decrease from 452 kA/m for x = 0–411 kA/m for x = 0.1. Coercivity (Hc) and magnetocrystalline anisotropy (K1) were also found to follow the same trend. Variation of the structural and magnetic parameters is attributed to the changes in the oxidation state of Co from 2 + to 3 + as it is confirmed from the results of XPS analysis.1 aAnantharamaiah, P., N.1 aJoy, P., A.  uhttps://library.ncl.res.in/content/effect-co-substitution-co2-and-v5-fe3-magnetic-properties-cofe2o4