RETRACTED ARTICLE: Synthesis, Structural and Magnetic Properties of Polypyrrole Coated Ni0.2Ca0.8Fe2O4 Nanocomposite

Abstract

The nanoparticles of spinel ferrites having composition Ni 0.2 Ca 0.8 Fe 2 O 4 were synthesized by an advanced sol-gel method and subsequently coated with intrinsically conducting polypyrrole (PPy) by chemical oxidative polymerization of the corresponding monomer (pyrrole) using ammonium peroxodisulphate as oxidant. The X-ray diffraction and TEM measurements were obtained to understand the crystalline structure, size and morphology of evolution of the samples. The dc electrical investigation revealed that at room temperature the surface conductivity increased from 2.8 × 10 −5 S cm −1 to 1.5 × 10 −3 S cm −1 on polymerization. Mössbauer investigations revealed that the polymerization causes migration of Fe 3+ ions from A to B site, resulting to the enhancement of the observed hyperfine field. In agreement with this, the dc magnetization measurements performed on VSM revealed an enhancement in saturation magnetization in the M-H curves on polymerization. The value of blocking temperature (T B ) is found to have credibly increased from 110 K to 130 K, which confirms the increase in crystallite size after polymerization.

Synthesis and physical properties of electromagnetic polypyrrole composites via addition of magnetic crystals

“…[1][2][3][4][5][6][7][8] In the past two decades, electromagnetic PPy has become one of the most attractive research topics due to its various potential applications. Electromagnetic PPy composites possess applicative potential as microwave absorbing materials, [9][10][11][12][13][14][15][16][17][18][19][20] adsorption materials, [21][22][23][24][25] electrocatalytic reagents to biospecies, 26 and specialized contrast agents for 1 H magnetic resonance imaging; 27 they also have potential applications in magnetic-controlled switches, 28 the magnetic separation of genomic DNA, 29 cancer cell targeting, 30 chemical sensing of H 2 O 2 , 31 and as biosensors. 32 Intrinsic magnetic PPy may be obtained via the control of the molecular structure during the synthesis of conducting PPy; also, electromagnetic PPy can be obtained via the incorporation of external magnetic crystals.…”

Spin injection behavior in conducting polymer coated superparamagnetically functional microstructures

“…The model studied here is a core-shell magnetopolymeric hybrid system. [1][2][3][4] The combination of these two classes of materials provides systems that are both interesting from a fundamental point of view and technological relevance, as they find the possibility of exploiting the potential of materials science research. It allows for engineering structures at the atomic level, with a large choice of building blocks, bottom-up fabrication and self-assembly, thereby opening up ways to experimentally study and understand key problems in solid-state physics such as quantum coherence, organic spintronics, magnetic interactions and the control of individual nanosystems.…”

“…The surface anisotropy adds to the total anisotropy in the case of small particles. 3 The blocking temperature varies increasingly with particle's crystallite size due to the corresponding increase in anisotropy energy compared to the thermal energy. By combining in a single material the electrical conductivity of conducting polymers and the magnetic properties of nanoferrites, new multifunctional materials have been developed.…”

“…By combining in a single material the electrical conductivity of conducting polymers and the magnetic properties of nanoferrites, new multifunctional materials have been developed. Recently, a great deal of interest has been given to the preparation of polymer coated nanoparticles of ferrites and has been found that the system retains superparamagnetism along with enhanced saturation magnetization and negligible increase in fractional weight, high surface conductivity, zero remanent magnetization, zero coercivity, 3 etc. This implies that the material can be appropriate for pursuing research to find application in various cutting edge technologies where the multifunctionality is taken to be the desperately needed feature.…”

“…This implies that the material can be appropriate for pursuing research to find application in various cutting edge technologies where the multifunctionality is taken to be the desperately needed feature. 3 In the present paper, the focus has been made to explore the evidence for spin injection phenomenon in functional hybrids of model viz., PPy coated Ni 0.5 Cu 0.5 Fe 2 O 4 . 11…”