Ferromagnetic and ferroelectric characteristics of Gd and Nd-substituted nickel ferrite were investigated. The materials formed in the cubic inverse spinel phase with small amounts of GdFeO3 and NdFeO3 as the additional phases in the respective materials. Substitution of Gd and Nd for Fe caused decrease in the saturation magnetization and Curie temperature of the nickel ferrite. However, the saturation magnetostriction is seen not to change significantly by the substitution of Gd and Nd. The existence of the ferroelectricity was confirmed from the ferroelectric loops and magnetocapacitance of -2% and -3% were observed. The large frequency dependence of the (high) dielectric constant reveals a wide dispersion of relaxation times. The ferroelectric transition temperature values of NiO.Fe1.95Gd0.05O3 and NiO.Fe1.95Nd0.05O3 were found to be 498 and 544 K, respectively. © 2009 Elsevier B.V. All rights reserved.

G. Markandeyulu

Department Of Physics

K. Kamala Bharathi

J. Arout Chelvane

Dielectric constants

FERROELECTRIC CHARACTERISTICS

FERROELECTRIC TRANSITION

FERROELECTRIC TRANSITION TEMPERATURE

Frequency dependence

INVERSE SPINEL

MAGNETOCAPACITANCE

Magnetoelectric properties

ND-DOPED

Nickel ferrite

SATURATION MAGNETOSTRICTION

Composite micromechanics

ferrite

Gadolinium

Magnetostriction

MAGNETOSTRICTIVE DEVICES

Neodymium

Nickel

Nickel alloys

Saturation magnetization

Ferroelectricity

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of Magnetism and Magnetic Materials

Cationic distribution and magnetic properties of partially rare-earth (R) doped NiFe2O4 (NFO) compounds, i.e. NiFe2- xRxO4 (x = 0 and 0.075; R = Gd, Dy and Ho) were investigated, and the results are discussed and presented in this paper. All the compounds were found to stabilize in the cubic inverse spinel structure with the space group Fd3-m. The analysis of the results based on X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) measurements are primarily focused on the valence state information of constituting rare-earth or transition-metal ions, cationic distribution, and the coupling between their magnetic moments. The XAS data revealed that nickel is in Ni2+ valence state while iron is mainly in the Fe3+ valence state though some perceptible traces of Fe2+ were observed. The rare-earth ions are in trivalent states. The partial doping causes differences in the cationic distribution of Ni2+ and Fe3+ ions which obviously results in differences in the net Fe or Ni magnetic moments. Furthermore, 57Fe Mössbauer spectra revealed altered hyperfine field parameters upon the Gd3+, Dy3+ and Ho3+ substitution and all the compounds were found to exhibit collinear ferrimagnetic structures. The results are relevant for the investigation of orientation of individual magnetic moments and to obtain site-specific information related to all the cations involved in the rare-earth doped nickel ferrite structures. © 2019

Cationic ordering and magnetic properties of rare-earth doped NiFe2O4 probed by Mössbauer and X-ray spectroscopies

We report on structural, spin glass behaviour and competing magnetic interactions in xNiFe2O4 - (1-x)BaTiO3 (x&nbsp;=&nbsp;0.2 and 0.3) nanocomposites prepared by sol-gel method. The structure and surface morphology of the NiFe2O4-BaTiO3 composites were examined by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD measurements of composite materials show the presence of both NiFe2O4 and BaTiO3 phases. FESEM and energy dispersive X-ray (EDX) measurements indicate uniformly distributed nano size particles and presence of Ni, Fe, O, Ba and Ti elements respectively. Temperature variation Raman spectra indicates large structural disordering (Peak broadening and shift) around 395&nbsp;K due to the structural transformation of BaTiO3. Magnetization, zero field cooled (ZFC) and field cooled (FC) measurements were carried out from 2&nbsp;K to 320&nbsp;K for both composites. ZFC and FC measurements reveal the spin glass and Superparamagnetism like behaviour along with competing magnetic interaction in both composites. Saturation magnetization value is seen to increase from 6.7 to 10&nbsp;emu/g with increasing Ni ferrite composition from x&nbsp;=&nbsp;0.2 to x&nbsp;=&nbsp;0.3. Distribution function associated with magnetocrystalline anisotropy energy barrier exhibits broad peaks due to the random distribution of spins associated with different particle size in the x&nbsp;=&nbsp;0.3 composition. © 2017 Elsevier B.V.

Competing magnetic interactions and superparamagnetism like behaviour in xNiFe2O4 - (1-x)BaTiO3 (x = 0.2 and 0.3) nano composites

NiFe2-xDyxO4 (x = 0, 0.1) compounds were prepared by solid state reaction. Room temperature X-ray diffraction confirmed the formation of the compounds in cubic inverse spinel phase with the space group Fd3m. Increments in the lattice constant were observed upon partial substitution of Fe3+ by Dy3+. While both magnetization and cubic magnetocrystalline anisotropy (K1) decreased with increasing temperature, with Dy3+ substitution, at any given temperature the magnetization decreased and K1 increased. A quantitative observation of direct magnetoelectric (DME) effect and qualitative observation of converse magnetoelectric (CME) effect in NiFe1.9Dy0.1O4 compound, describe its multiferroic nature. © 2015 The Authors. Published by Elsevier B.V.

Fulltext

Physics Procedia

Anisotropy, Magnetostriction and Converse Magnetoelectric Effect in Dy Substituted Ni Ferrite

The structural and magnetic properties of bulk polycrystalline CoFe 2O4 and niobium substituted Co1.1Fe 1.85Nb0.05O4 prepared by solid state reaction method, are presented in this paper. The lattice parameter of Co 1.1Fe1.85Nb0.05O4 is seen to be more than that of CoFe2O4. Saturation magnetization, first order magnetocrystalline anisotropy constant calculated using law of approach to saturation and magnetostriction of Co1.1Fe1.85Nb 0.05O4 are seen to be less than those of CoFe 2O4. Longitudinal magnetostriction of Co 1.1Fe1.85Nb0.05O4 measured at room temperature is -123 × 10-6 at a field of 2.2 kOe, with enhanced strain derivative. Field induced trigonal distortion was observed at 2.2 kOe in Co1.1Fe1.85Nb0.05O4 from the analysis of powder XRD patterns. Co1.1Fe1.85Nb 0.05O4 exhibits ferroelectric and magnetoelectric properties. © 2014 Elsevier B.V. All rights reserved.

Journal of Alloys and Compounds

Structural, magnetic and magnetoelectric properties of Nb substituted Cobalt Ferrite

Emissions Inventory Report Summary for Los Alamos National Laboratory for Calendar Year 2006

Physics Letters A

The studies of nanocrystalline Ni0.7Mn0.3NdxFe2–xO4 () ferrites

The influences of Zn2+ and some rare-earth ions on the magnetic properties of nickel–zinc ferrites

Journal of Applied Physics

Nanostructure magneto-optical thin films of rare earth (RE=Gd,Tb,Dy) doped cobalt spinel by sol–gel synthesis

The influence of frustration on the magnetostriction of the ferrites–cromites of copper

Magnetoelectric properties of Gd and Nd-doped nickel ferrite

Journal	Data powered by TypesetJournal of Magnetism and Magnetic Materials
Publisher	Data powered by TypesetElsevier
ISSN	03048853
Open Access	No