Synthesis, phase composition, Mossbauer and magnetic characterization of iron oxide nanoparticles

The present work describes the synthesis of iron oxide nanoparticles by thermal decomposition of Fe-precursors in argon and vacuum environments with control over particle size distribution, phase composition and the resulting magnetic properties. The Rietveld analysis of X-ray diffraction data revealed the crystallinity as well the single-phase of g-Fe2O3 nanoparticles prepared under vacuum, whereas the argon environment leads to the formation of multi-phase composition of g-Fe2O3/Fe3O4 (90%) and wustite (10%). Synchrotron X-ray absorption near edge structure (XANES) indicates that the predominant phase in both the samples is g-Fe2O3, which is subsequently verified from the Mo¨ssbauerspectra. DC magnetic measurements indicate behavior typical of a superparamagnetic system validated by Mo¨ssbauer analysis. However, further investigation of ac susceptibility by typical Ne´el?Arrhenius andVogel Fulcher magnetic models suggests an influence of interparticle interactions on the overall magnetic behavior of the system.Instituto de Física La Plat

Synthesis, phase composition, Mossbauer and magnetic characterization of iron oxide nanoparticles

The present work describes the synthesis of iron oxide nanoparticles by thermal decomposition of Fe-precursors in argon and vacuum environments with control over particle size distribution, phase composition and the resulting magnetic properties. The Rietveld analysis of X-ray diffraction data revealed the crystallinity as well the single-phase of g-Fe2O3 nanoparticles prepared under vacuum, whereas the argon environment leads to the formation of multi-phase composition of g-Fe2O3/Fe3O4 (90%) and wustite (10%). Synchrotron X-ray absorption near edge structure (XANES) indicates that the predominant phase in both the samples is g-Fe2O3, which is subsequently verified from the Mo¨ssbauerspectra. DC magnetic measurements indicate behavior typical of a superparamagnetic system validated by Mo¨ssbauer analysis. However, further investigation of ac susceptibility by typical Ne´el?Arrhenius andVogel Fulcher magnetic models suggests an influence of interparticle interactions on the overall magnetic behavior of the system.Instituto de Física La Plat

Exchange Bias Field In Mixed Arrangement Of Nio-ni Nanoparticles

Three samples of naturally mixed Ni (>120 nm) and NiO (similar to 10 nm) were prepared with different particle diameters/distributions and amount of metallic nickel. Exchange bias effect has been observed and strongly depends upon both particle sizes/distributions and concentration of Ni, achieving the highest value (similar to 2200 Oe at 5 K) for the pure NiO, while the corresponding value for the sample with maximum Ni concentration is similar to 70 Oe. This is tentatively explained taking into account the effect of induced dipolar field by bigger Ni particles on the stabilization of magnetically ordered surface regions of the smaller NiO nanoparticles.1731DAE Solid State Physics SymposiumDEC 21-25, 2015Amity Univ, Noida, INDI

Exchange bias field in mixed arrangement of NiO-Ni nanoparticles

Three samples of naturally mixed Ni (>120 nm) and NiO (similar to 10 nm) were prepared with different particle diameters/distributions and amount of metallic nickel. Exchange bias effect has been observed and strongly depends upon both particle sizes/distributions and concentration of Ni, achieving the highest value (similar to 2200 Oe at 5 K) for the pure NiO, while the corresponding value for the sample with maximum Ni concentration is similar to 70 Oe. This is tentatively explained taking into account the effect of induced dipolar field by bigger Ni particles on the stabilization of magnetically ordered surface regions of the smaller NiO nanoparticles1731DAE Solid State Physics Symposium2015-12-21Amity Univ, Noida, Indiasem informaçã

Investigation of structural, magnetic and Mossbauer properties of Co2+ and Cu2+ substituted Ni-Zn nanoferrites

We investigated the effects of Co2+ and Cu2+ substitution on the super-exchange interactions in Ni-Zn nanoferrites. The cation distribution technique was taken into account to explain the results. To authenticate the cation distribution, we have estimated the cation distribution in the light of X-ray diffraction method, Mossbauer spectroscopic analysis, and magnetization study. Statistical model based on the cation distribution was used to calculate the Curie temperature. The values of magneton number n(B) and Curie temperature T-c calculated by using the cation distribution is found to be in agreement with the experimentally obtained values

Room Temperature Long Range Ferromagnetic Ordering in Ni0.58Zn0.42Co0.10Cu0.10Fe1.8O4 Nano magnetic System

The structural and magnetic behavior of sol-gel autocombustion synthesized nanocrystalline Ni0.58Zn0.42Co0.10Cu0.10Fe1.8O4 have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), Mossbauer spectroscopy and vibrating sample magnetometer(VSM). Sample of high purity and high homogeneity was obtained by calcination at low temperature (500 degrees C) resulting in nanoparticles of average diameter similar to 15nm as determined by XRD and further confirmed by TEM. X-ray diffraction (XRD) and selective area diffraction (SAED) confirmed the single phase of the sample. Mossbauer results are supported by magnetization data. Well defined sextets and appearance of hysteresis at room temperature indicate the existence of ferromagnetic coupling at room temperature finding material utility in magnetic storage data. The existence of iron in ferric state confirmed by isomer shift is a clear evidence of improved magnetic properties of the present system

Synthesis, phase composition, Mossbauer and magnetic characterization of iron oxide nanoparticles

The present work describes the synthesis of iron oxide nanoparticles by thermal decomposition of Fe-precursors in argon and vacuum environments with control over particle size distribution, phase composition and the resulting magnetic properties. The Rietveld analysis of X-ray diffraction data revealed the crystallinity as well the single-phase of g-Fe2O3 nanoparticles prepared under vacuum, whereas the argon environment leads to the formation of multi-phase composition of g-Fe2O3/Fe3O4 (90%) and wustite (10%). Synchrotron X-ray absorption near edge structure (XANES) indicates that the predominant phase in both the samples is g-Fe2O3, which is subsequently verified from the Mo¨ssbauerspectra. DC magnetic measurements indicate behavior typical of a superparamagnetic system validated by Mo¨ssbauer analysis. However, further investigation of ac susceptibility by typical Ne´el?Arrhenius andVogel Fulcher magnetic models suggests an influence of interparticle interactions on the overall magnetic behavior of the system.Fil: Sarveena. H. P. University; IndiaFil: Vargas, Jose Marcelo. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia de Física. Laboratorio de Resonancias Magnéticas; ArgentinaFil: Shukla, D. K.. UGC DAE Consortium for Scientific Research; IndiaFil: Meneses, Cristiano T.. Núcleo de Pós-Graduaçao em Física, Campus Prof. José Aluísio de Campos, UFS; BrasilFil: Mendoza Zélis, Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Singh, M.. H. P. University; IndiaFil: Sharma, Surender. H. P. University; Indi

Surface and interface interplay on the oxidizing temperature of iron oxide and Au-iron oxide core-shell nanoparticles

This article presents the effect of oxidation temperature on shape anisotropy, phase purity and growth of core-shell heterostructures and consequently their effect on structure-property relationships. Iron oxide and Au-iron oxide nanocomposites were synthesized by a thermal decomposition method by passing pure oxygen at different temperatures (125-250 °C). The prepared nanoparticles were surface functionalized by organic molecules; the presence of the organic canopy prevented both direct particle contact as well as further oxidation, resulting in the stability of the nanoparticles. We have observed a systematic improvement in the core and shell shape through tuning the reaction time as well as the oxidizing temperatures. Spherical and spherical triangular shaped core-shell structures have been obtained at an optimum oxidation temperature of 125 °C and 150 °C for 30 minutes. However, further increase in the temperature as well as oxidation time results in core-shell structure amendment and results in fully grown core-shell heterostructures. As stability and ageing issues limit the use of nanoparticles in applications, to ensure the stability of the prepared iron oxide nanoparticles we performed XRD analysis after more than a year and they remained intact showing no ageing effect. Specific absorption rate values useful for magnetic fluid hyperthermia were obtained for two samples on the basis of detailed characterization using X-ray diffraction, high-resolution transmission electron microscopy, Mössbauer spectroscopy, and dc-magnetization experiments.Instituto de Física La Plat

Surface and interface interplay on the oxidizing temperature of iron oxide and Au-iron oxide core-shell nanoparticles

This article presents the effect of oxidation temperature on shape anisotropy, phase purity and growth of core-shell heterostructures and consequently their effect on structure-property relationships. Iron oxide and Au-iron oxide nanocomposites were synthesized by a thermal decomposition method by passing pure oxygen at different temperatures (125-250 °C). The prepared nanoparticles were surface functionalized by organic molecules; the presence of the organic canopy prevented both direct particle contact as well as further oxidation, resulting in the stability of the nanoparticles. We have observed a systematic improvement in the core and shell shape through tuning the reaction time as well as the oxidizing temperatures. Spherical and spherical triangular shaped core-shell structures have been obtained at an optimum oxidation temperature of 125 °C and 150 °C for 30 minutes. However, further increase in the temperature as well as oxidation time results in core-shell structure amendment and results in fully grown core-shell heterostructures. As stability and ageing issues limit the use of nanoparticles in applications, to ensure the stability of the prepared iron oxide nanoparticles we performed XRD analysis after more than a year and they remained intact showing no ageing effect. Specific absorption rate values useful for magnetic fluid hyperthermia were obtained for two samples on the basis of detailed characterization using X-ray diffraction, high-resolution transmission electron microscopy, Mössbauer spectroscopy, and dc-magnetization experiments.Fil: Sarveena. Himachal Pradesh University; IndiaFil: Muraca, Diego. Universidade Estadual de Campinas; Brasil. Universidade Federal Do Abc;Fil: Mendoza Zélis, Pedro. Instituto de Física la Plata (conicet- Universidad Nacional de la Plata); ArgentinaFil: Javed, Y.. University Of Agriculture, Faisalabad; PakistánFil: Ahmad, N.. Université Paris Diderot - Paris 7; FranciaFil: Vargas, Jose Marcelo. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Moscoso Londoño, O.. Universidade Estadual de Campinas; BrasilFil: Knobel, M.. Universidade Estadual de Campinas; Brasil. Centro Nacional de Pesquisa Em Energia E Materiais;Fil: Singh, M.. Himachal Pradesh University; IndiaFil: Sharma, S.K.. Universidade Federal Do Maranhao; . Himachal Pradesh University; Indi