01459nas a2200157 4500008004100000022001400041245012400055210006900179260012500248300001100373490000800384520073600392100002801128700002501156856012001181 2012 eng d a0003-695100aHigh magnetostriction and coupling coefficient for sintered cobalt ferrite derived from superparamagnetic nanoparticles0 aHigh magnetostriction and coupling coefficient for sintered coba aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScAUG a0724050 v1013 a

High magnetostriction (lambda) and coupling coefficient (d lambda/dH) of 315 ppm and 1.97 x 10(-9) A(-1) m, respectively, are obtained at room temperature for sintered cobalt ferrite derived from nanocrystalline powders. Also, the powder was compacted at a low pressure of 8 MPa and sintered for a short duration of 10 min at 1450 degrees C. Magnetic annealing at 300 degrees C in a field of 0.5 T for 30 min further enhanced the magnetostriction coefficient to 345 ppm with a higher coupling coefficient 2.12 x 10(-9) A(-1)m. The magnetic field above which maximum magnetostriction is observed is reduced by almost half after magnetic annealing. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4745922]

1 aMohaideen, Kamal, Khaja1 aJoy, Pattayil, Alias uhttps://library.ncl.res.in/content/high-magnetostriction-and-coupling-coefficient-sintered-cobalt-ferrite-derived-001798nas a2200217 4500008004100000022001400041245014400055210006900199260007300268300001400341490000700355520092600362653001901288653002901307653002101336653002001357653002001377100002801397700002501425856013001450 2013 eng d a1567-173900aHigh magnetostriction coefficient of Mn substituted cobalt ferrite sintered from nanocrystalline powders and after magnetic field annealing0 aHigh magnetostriction coefficient of Mn substituted cobalt ferri aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT a1697-17010 v133 a

Magnetostriction characteristics of Mn substituted cobalt ferrite, CoFe2-xMnxO4 (0 <= x <= 0.3), sintered from nanocrystalline powders of average particle size of similar to 4 nm have been studied. Larger value of magnetostriction at lower magnetic field is achieved after substitution of Mn for Fe. The maximum value of magnetostriction coefficient is not much affected and the slope of the magnetostriction is increased with increasing Mn content. Higher maximum value of magnetostriction coefficient (lambda) of 234 ppm comparable to that of the unsubstituted composition with larger strain derivative (d lambda/dH) is obtained for x = 0.2 in CoFe2-xMnxO4. The magnetostriction coefficient is increased to 262 ppm with further enhancement in the strain derivative after annealing the sintered compact at 300 degrees C in a magnetic field of 400 kA/m for 30 min. (C) 2013 Elsevier B.V. All rights reserved.

10aCobalt ferrite10aMagnetic field annealing10aMagnetostriction10aMn substitution10aNanocrystalline1 aMohaideen, Kamal, Khaja1 aJoy, Pattayil, Alias uhttps://library.ncl.res.in/content/high-magnetostriction-coefficient-mn-substituted-cobalt-ferrite-sintered-nanocrystalline-001776nas a2200193 4500008004100000022001400041245011300055210006900168260007300237300001200310490000800322520100800330653001901338653002101357653002401378100002801402700002501430856012701455 2014 eng d a0304-885300aHigh magnetostriction parameters for low-temperature sintered cobalt ferrite obtained by two-stage sintering0 aHigh magnetostriction parameters for lowtemperature sintered cob aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC a121-1290 v3713 a

From the studies on the magnetostriction characteristics of two-stage sintered polycrystalline CoFe2O4 made from nanocrystalline powders, it is found that two-stage sintering at low temperatures is very effective for enhancing the density and for attaining higher magnetostriction coefficient. Magnetostriction coefficient and strain derivative are further enhanced by magnetic field annealing and relatively larger enhancement in the magnetostriction parameters is obtained for the samples sintered at lower temperatures, after magnetic annealing, despite the fact that samples sintered at higher temperatures show larger magnetostriction coefficients before annealing. A high magnetostriction coefficient of similar to 380 ppm is obtained after field annealing for the sample sintered at 1100 degrees C, below a magnetic field of 400 kA/m, which is the highest value so far reported at low magnetic fields for sintered polycrystalline cobalt ferrite. (C) 2014 Elsevier B.V. All rights reserved.

10aCobalt ferrite10aMagnetostriction10aTwo-stage sintering1 aMohaideen, Kamal, Khaja1 aJoy, Pattayil, Alias uhttps://library.ncl.res.in/content/high-magnetostriction-parameters-low-temperature-sintered-cobalt-ferrite-obtained-two-0