@article {45747, title = {High magnetostriction parameters of sintered and magnetic field annealed Ga-substituted CoFe2O4}, journal = {Materials Letters}, volume = {192}, year = {2017}, month = {APR }, pages = {169-172}, type = {Article}, abstract = {

Impact of substitution of the non-magnetic ion Ga3+ for Fe3+ on the magnetostriction parameters of CoFe2O4 has been investigated for samples prepared by a tartrate-gel method. All the Ga-substituted compositions in CoGaxFe2-xO4 (0 \<= x \<= 0.3) showed higher strain sensitivity (d lambda/dH), at low magnetic fields, compared to that of the unsubstituted sample. The magnetostriction strain (lambda) and d lambda/dH of the composition CoGa0.1Fe1.9O4 could be enhanced from -228 to -296 ppm and -2.20 x 10(-9) to -3.55 x 10(-9) miA, respectively, at low magnetic fields, after magnetic field annealing at 300 degrees C. (C) 2016 Elsevier B.V. All rights reserved.

}, keywords = {Cobalt ferrite, Magnetic field annealing, Magnetic materials, Magnetostriction, Substitution}, issn = {0167-577X}, doi = {10.1016/j.matlet.2016.12.031}, author = {Anantharamaiah, P. N. and Joy, P. A.} } @article {45491, title = {Large enhancement in the magnetostriction parameters of the composite of CoFe2O4 and CoFe1.9Ga0.1O4}, journal = {Materials Letters}, volume = {236}, year = {2019}, month = {FEB }, pages = {303-306}, type = {Article}, abstract = {

A new strategy to enhance the magnetostriction parameters of cobalt ferrite (CoFe2O4) is illustrated. A composite comprising of nanocrystalline CoFe2O4 and bulk CoFe(1.9)Ga(0.1)O(4 )powders were mixed together then compacted and sintered at 1450 degrees C for 10 min. For a composite of 70 wt\% CoFe2O4 and 30 wt\% of CoFe(1.9)Ga(0.1)O4, maximum magnetostriction coefficient (lambda(max)) of -350 ppm has been obtained at lower magnetic field which is nearly 20\% and 65\% higher than that obtained for CoFe2O4 and CoFe1.9Ga0.1O4, respectively. Moreover, the composite exhibited higher strain sensitivity [d lambda/dH](max )of -2.6 x 10 (9) A(-1) m against the individual components of the composite. (C) 2018 Published by Elsevier B.V.

}, keywords = {Ceramics, Composite materials, Magnetic materials}, issn = {0167-577X}, doi = {10.1016/j.matlet.2018.10.115}, author = {Anantharamaiah, P. N. and Joy, P. A.} } @article {46074, title = {Magnetic parameters of SrFe12O19 sintered from a mixture of nanocrystalline and micron-sized powders}, journal = {Ceramics International}, volume = {45}, year = {2019}, month = {JUL}, pages = {13592-13596}, type = {Article}, abstract = {

Obtaining higher magnetic parameters is essential for high-power sintered strontium ferrite (SrFe12O19) for various applications. A novel approach has been made to improve the magnetic parameters of sintered strontium ferrite by making self-composites from nano and micron-sized powders. Powders with two different weight ratios (50 wt\% nano:50 wt\% micron and 75 wt\% nano:25 wt\% micron) were mixed together, compacted and sintered at 1200 degrees C for 1 h. For a self-composite of 75 wt\% nano and 25 wt\% micron-sized powders, coercivity (H-c) of 3076 Oe has been obtained, larger than the values for the sintered compacts from the component powders. The present study suggests that the magnetic parameters of sintered SrFe12O19 can be improved by making self-composite comprising of nanocrystalline and micron-sized powders.

}, keywords = {Ceramics, Magnetic materials, microstructures, Self-composites, strontium ferrite}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2019.04.023}, author = {Shashanka, H. M. and Anantharamaiah, P. N. and Joy, P. A.} }