Mahdi Ghazanfari - Academia.edu (original) (raw)

Papers by Mahdi Ghazanfari

Research paper thumbnail of Synthesis and characterization of Fe3O4@Ag core-shell: structural, morphological, and magnetic properties

This paper is a report on the synthesis of the Fe3O4@Ag core-shell with high saturation magnetiza... more This paper is a report on the synthesis of the Fe3O4@Ag core-shell with high saturation magnetization of magnetite nanoparticles as the core, by using polyol route and silver shell by chemical reduction. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy analyses confirmed that the particles so produced were monophase. The magnetic properties of the product were investigated by using a vibrating sample magnetometer. Magnetic saturation of magnetite was 91 emu/g that around about bulk magnetization. This high saturation magnetization can be attributed to the thin dead layer. By using polyethylene glycol as a surfactant to separate and restrict the growth of the particles, magnetostatic interactions are in good agreement with the remanence ratio analysis. Morphology and the average size of the particles were determined with field emission scanning electron microscope (FESEM). Spherical aggregates of Fe3O4 (size around 73 nm) are composed of a small primary particle si...

Research paper thumbnail of Synthesis and characterization of Graphene in high yield with new method

Optics and Photonics Society of Iran, Feb 15, 2014

Graphene's unique properties make it a good candidate for the design of next-generation electroni... more Graphene's unique properties make it a good candidate for the design of next-generation electronic and optical devices. Graphene suffers from a problem that is common to many novel Materials, the lack of a method for producing it at high yields. In this study high-quality few layer graphene was synthesized via solution-phase exfoliation of graphite in N-Methyle-pyrrolidone (NMP). The presence of multi-layer graphene confirmed by Raman spectroscopy and UV-visible spectroscopy showed the absorbance peak of synthesized graphene in 310 nm and it was a proof that graphene was composed.

Research paper thumbnail of Influence of MWCNTs on the formation, structure and magnetic properties of magnetite

Materials Science in Semiconductor Processing, 2015

Research paper thumbnail of Light trapping effect in plasmonic blockade at the interface of Fe 3 O 4 @Ag core/shell

RSC Adv., 2015

Spherical isotropic Fe3O4 nanoparticles were coated with Ag-shell in order to investigate the pos... more Spherical isotropic Fe3O4 nanoparticles were coated with Ag-shell in order to investigate the possibility of trapping photons through plasmon or plasmonic energy transfer at the magnetic–plasmonic interface coupling structure of core/shell.

Research paper thumbnail of The effect of particle size on the characteristics of FeCo nanoparticles

Solid State Communications, 2010

Some size-dependent characteristics of FeCo nanoparticles are investigated in this paper. The nan... more Some size-dependent characteristics of FeCo nanoparticles are investigated in this paper. The nanoparticles are fabricated using a coprecipitation route and their sizes are controlled by changing the reaction time. Transverse electron microscopy (TEM) images show that the nanoparticles are all spherical with an average size of 2-6 nm. The average size obtained from X-ray diffraction (XRD) measurements is in the range 1-3 nm. Magnetic measurements reveal that the nanoparticles are ordered ferromagnetically and have a high coercivity of about 500 Oe. In our measurements, the coercivity was decreased with decreasing particle size, indicating that the nanoparticles were in a single-domain region. Production of FeCo nanoparticles with high coercivity and fine dimension is highly promising for future recording media technology.

Research paper thumbnail of Why and How the Zigzag Edge of Suspended Graphene Sheet where Deformed

The edge of graphene plays an important role in electronic and spintronic properties of graphene.... more The edge of graphene plays an important role in electronic and spintronic properties of graphene. As we know in many article zigzag edge used as stable edge but this edge cannot be true edge. When the graphene sheet is cut, bonds are broken along this line and electrons that participate in bond be free, so there is electron density gradient along the edge. Because of this the carbon atoms along the edge is moved till the stable structure be established. For achieving to this specific structure, density functional theory was used via Gaussian package. The result shows hexagons on the edge are going to deform to pentagon and heptagon by change the kind of bond in this chain. In the other zigzag chain behind the edge we have movement of electron density from one carbon atom to another carbon atom by help of carbon atom that placed between them. So we suggested new edge that can be replacement by zigzag edge in calculation with more less structure energy that identify in experiment method too.

Research paper thumbnail of Synthesis and characterization of Fe3O4@Ag core-shell: structural, morphological, and magnetic properties

This paper is a report on the synthesis of the Fe3O4@Ag core-shell with high saturation magnetiza... more This paper is a report on the synthesis of the Fe3O4@Ag core-shell with high saturation magnetization of magnetite nanoparticles as the core, by using polyol route and silver shell by chemical reduction. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy analyses confirmed that the particles so produced were monophase. The magnetic properties of the product were investigated by using a vibrating sample magnetometer. Magnetic saturation of magnetite was 91 emu/g that around about bulk magnetization. This high saturation magnetization can be attributed to the thin dead layer. By using polyethylene glycol as a surfactant to separate and restrict the growth of the particles, magnetostatic interactions are in good agreement with the remanence ratio analysis. Morphology and the average size of the particles were determined with field emission scanning electron microscope (FESEM). Spherical aggregates of Fe3O4 (size around 73 nm) are composed of a small primary particle si...

Research paper thumbnail of Synthesis and characterization of Graphene in high yield with new method

Optics and Photonics Society of Iran, Feb 15, 2014

Graphene's unique properties make it a good candidate for the design of next-generation electroni... more Graphene's unique properties make it a good candidate for the design of next-generation electronic and optical devices. Graphene suffers from a problem that is common to many novel Materials, the lack of a method for producing it at high yields. In this study high-quality few layer graphene was synthesized via solution-phase exfoliation of graphite in N-Methyle-pyrrolidone (NMP). The presence of multi-layer graphene confirmed by Raman spectroscopy and UV-visible spectroscopy showed the absorbance peak of synthesized graphene in 310 nm and it was a proof that graphene was composed.

Research paper thumbnail of Influence of MWCNTs on the formation, structure and magnetic properties of magnetite

Materials Science in Semiconductor Processing, 2015

Research paper thumbnail of Light trapping effect in plasmonic blockade at the interface of Fe 3 O 4 @Ag core/shell

RSC Adv., 2015

Spherical isotropic Fe3O4 nanoparticles were coated with Ag-shell in order to investigate the pos... more Spherical isotropic Fe3O4 nanoparticles were coated with Ag-shell in order to investigate the possibility of trapping photons through plasmon or plasmonic energy transfer at the magnetic–plasmonic interface coupling structure of core/shell.

Research paper thumbnail of The effect of particle size on the characteristics of FeCo nanoparticles

Solid State Communications, 2010

Some size-dependent characteristics of FeCo nanoparticles are investigated in this paper. The nan... more Some size-dependent characteristics of FeCo nanoparticles are investigated in this paper. The nanoparticles are fabricated using a coprecipitation route and their sizes are controlled by changing the reaction time. Transverse electron microscopy (TEM) images show that the nanoparticles are all spherical with an average size of 2-6 nm. The average size obtained from X-ray diffraction (XRD) measurements is in the range 1-3 nm. Magnetic measurements reveal that the nanoparticles are ordered ferromagnetically and have a high coercivity of about 500 Oe. In our measurements, the coercivity was decreased with decreasing particle size, indicating that the nanoparticles were in a single-domain region. Production of FeCo nanoparticles with high coercivity and fine dimension is highly promising for future recording media technology.

Research paper thumbnail of Why and How the Zigzag Edge of Suspended Graphene Sheet where Deformed

The edge of graphene plays an important role in electronic and spintronic properties of graphene.... more The edge of graphene plays an important role in electronic and spintronic properties of graphene. As we know in many article zigzag edge used as stable edge but this edge cannot be true edge. When the graphene sheet is cut, bonds are broken along this line and electrons that participate in bond be free, so there is electron density gradient along the edge. Because of this the carbon atoms along the edge is moved till the stable structure be established. For achieving to this specific structure, density functional theory was used via Gaussian package. The result shows hexagons on the edge are going to deform to pentagon and heptagon by change the kind of bond in this chain. In the other zigzag chain behind the edge we have movement of electron density from one carbon atom to another carbon atom by help of carbon atom that placed between them. So we suggested new edge that can be replacement by zigzag edge in calculation with more less structure energy that identify in experiment method too.