Synthesis of Face-Centered Tetragonal FePt Nanoparticles and Granular Films from Pt@Fe2O3Core−Shell Nanoparticles

2003 ◽  
Vol 125 (47) ◽  
pp. 14559-14563 ◽  
Author(s):  
Xiaowei Teng ◽  
Hong Yang
Keyword(s):  
Fept Nanoparticles ◽  
Shell Nanoparticles ◽  
Granular Films ◽  
Face Centered

Synthesis and Magnetic Properties of FePt /Silica Core-Shell Nanoparticles

2010 ◽  
Vol 178 ◽  
pp. 291-295 ◽  
Author(s):  
Cui Xia Li ◽  
Zhi Hong Li ◽  
Xue Yan Du ◽  
Hai Xia Guo
Keyword(s):  
Magnetic Properties ◽  
Reverse Micelles ◽  
Core Shell ◽  
Fept Nanoparticles ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
Transmission Electron ◽  
Face Centered ◽  
Core Shell Nanoparticles

FePt nanoparticles (NPS), ~2nm in diameter, were synthesized and then coated with silica (SiO2) shells ~1.5nm-thick using reverse micelles as nanoreactors. The silica-coated FePt core–shell (FePt @silica) NPS were characterized by direct techniques of transmission electron microscopy (TEM). The results showed that the silica shells prevented the aggregation in liquid comparing to their bare counterparts. The as-synthesized FePt@SiO2 NPS exhibited essential characteristics of superparamagnetic behavior, as investigated by a vibrating sample magnetometer (VSM). X-ray diffraction (XRD) studies proved that the annealing at 700 °C for 30min under argon atmosphere caused the crystal structure of FePt core to transform from disordered face centered cubic (fcc) to the chemically ordered L10 FePt with face-centered tetragonal (fct) structure. This phase transition caused the change of magnetic properties of the FePt@SiO2 particles from superparamagnetism to ferromagnetism.

Synthesis and Characterization of L10 FePt Nanoparticles from Pt(Au, Ag)/γ-Fe2O3 Core-Shell Nanoparticles

2005 ◽  
Vol 17 (18) ◽  
pp. 2188-2192 ◽  
Author(s):  
V. Tzitzios ◽  
D. Niarchos ◽  
G. Hadjipanayis ◽  
E. Devlin ◽  
D. Petridis
Keyword(s):  
Synthesis And Characterization ◽  
Core Shell ◽  
Fept Nanoparticles ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

Synthesis and Magnetic Properties of FePt Nanoparticles with Hard Nonmagnetic Shells

2007 ◽  
Vol 7 (1) ◽  
pp. 350-355 ◽  
Author(s):  
Shishou Kang ◽  
Shifan Shi ◽  
G. X. Miao ◽  
Zhiyong Jia ◽  
David E. Nikles ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Crystallographic Orientation ◽  
Sol Gel ◽  
Molar Ratio ◽  
Core Shell ◽  
Fept Nanoparticles ◽  
Shell Nanoparticles ◽  
Spherical Core ◽  
Size And Morphology ◽  
Core Shell Nanoparticles

Chemically synthesized FePt nanoparticles were coated with nonmagnetic SiO2 and MnO shells by sol–gel and polyol processes. TEM images show that the FePt/SiO2 nanoparticles exhibit a thick spherical shell. The size and morphology of the MnO shell can be controlled by changing the reaction temperature, the molar ratio of surfactants/Mn(acac)2, and/or the concentration of precursor. The morphology of the MnO shell can be either spherical-like or cubic-like, depending on whether the molar ratio of surfactants/Mn(acac)2 is less than or larger than 2. From XRD measurements, the spherical core/shell nanoparticles exhibit 3D random crystallographic orientation, while the cubic core/shell nanoparticles prefer (200) texture. The magnetic moment of FePt particles can be enhanced by coating with SiO2 and MnO shells. Furthermore, the agglomeration of FePt particles upon the thermal annealing can be significantly inhibited with SiO2 and MnO shells.

Novel Nanohybrids Derived from the Attachment of FePt Nanoparticles on Carbon Nanotubes

2008 ◽  
Vol 8 (11) ◽  
pp. 5942-5951 ◽  
Author(s):  
Theodoros Tsoufis ◽  
Aphrodite Tomou ◽  
Dimitrios Gournis ◽  
Alexios P. Douvalis ◽  
Ioannis Panagiotopoulos ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Carbon Nanotubes ◽  
Particle Size ◽  
Fept Nanoparticles ◽  
Face Centered Cubic ◽  
Magnetization Measurements ◽  
Hybrid Sample ◽  
The Face ◽  
Face Centered ◽  
Mwcnts Surface

Multiwalled carbon nanotubes (MWCNTs) were used as nanotemplates for the dispersion and stabilization of FePt nanoparticles (NPs). Pre-formed capped FePt NPs were connected to the MWCNTs external surface via covalent binding through organic linkers. Free FePt NPs and MWCNTs-FePt hybrids were annealed in vacuum at 700 °C in order to achieve the L10 ordering of the FePt phase. Both as prepared and annealed samples were characterized and studied using a combination of experimental techniques, such as Raman and Mössbauer spectroscopies, powder X-ray Diffraction (XRD), magnetization and transmittion electron microscopy (TEM) measurements. TEM measurements of the hybrid sample before annealing show that a fine dispersion of NPs along the MWCNTs surface is achieved, while a certain amount of free particles attached to each other in well connected dense assemblies of periodical or non-periodical particle arrangements is also observed. XRD measurements reveal that the FePt phase has the face-centered cubic (fcc) disordered crystal structure in the as prepared samples, which is transformed to the face-centered tetragonal (fct) L10 ordered crystal structure after annealing. An increase in the average particle size is observed after annealing, which is higher for the free NPs sample. Superparamagnetic phenomena due to the small FePt particle size are observed in the Mössbauer spectra of the as prepared samples. Mössbauer and magnetization measurements of the MWCNTs-FePt hybrids sample reveal that the part of the FePt particles attached to the MWCNTs surface shows superparamagnetic phenomena at RT even after the annealing process. The hard magnetic L10 phase characteristics are evident in the magnetization measurements of both samples after annealing, with the coercivity of the hybrid sample over-scaling that of the free NPs sample by a factor of 1.25.

Polystyrene coated iron-platinum drug delivery platforms for theranostics

2016 ◽  
Author(s):  
◽  
Emilia Ohsone-Zargham Mason
Keyword(s):  
Drug Delivery ◽  
Magnetic Resonance ◽  
Unit Cell ◽  
Polymerization Reaction ◽  
Fept Nanoparticles ◽  
X Ray ◽  
Iron Platinum ◽  
Beta Cyclodextrin ◽  
Cell Structures ◽  
Face Centered

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Cancer is the second leading cause of death in the United States, exceeded only by heart disease, and it is estimated that one in every four deaths is due to cancer.1 Many therapeutic techniques that are currently used are often severely limited and can cause adverse effects, which prevents the aggressive treatment of late stage cancers. Significant improvements are needed involving early detection and more selective treatment options. Much interest has been shown in the development of materials that are highly selective and capable of being used in both therapeutic and diagnostic applications.2,3 nanoparticles have been shown to passively accumulate in tumors, making them useful materials for developments in cancer research.4 Iron-platinum (FePt) nanoparticles have an excellent potential as delivery agents for medicinal applications. Superparamagnetic FePt nanoparticles were embedded in a surface-functionalized polymeric shell as drug delivery platforms. The FePt core offers improved characteristics for magnetic resonance imaging (MRI) over currently used materials. The FePt nanoparticles were optimized to sizes between 2 to 6 nanometers and their physical and magnetic properties were also analyzed. The amount of surfactants used during the synthesis had a significant effect on the size and shape of the nanoparticles. The altered synthetic parameters resulted in the formation of both cubic and spherical nanoparticles. Face-centered cubic (fcc) unit cell structures were produced, which could also be thermally annealed to form the more ordered face-centered tetragonal (fct) structures. The fcc and fct unit cell structures of the FePt nanoparticles were characterized using powder X-ray diffraction (XRD). The FePt nanoparticle cores were coated using an emulsion polymerization reaction to increase their stability in biological systems.5 The polystyrene coating was optimized to produce an overall size of approximately 12 to 30 nanometers. The magnetic characteristics of the coated FePt nanoparticles were analyzed by MRI. Dynamic light scattering (DLS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and inductively coupled plasma mass spectrometry (ICP-MS) were also used to characterize the size and composition of the nanoparticles. The coated nanoparticles were functionalized with azides on the surface and analyzed using both Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). beta-cyclodextrin was attached to the surface of the nanoparticles using a click chemistry reaction. The hydrophobic cavity of the beta-cyclodextrin allows for the incorporation of hydrophobic drugs for subsequent delivery. These superparamagnetic FePt coated and functionalized nanoparticles show great potential to selectively treat and diagnosis various types of cancer and diseases.6 Furthermore, there are numerous drugs such as FK866, doxorubicin, gemcitabine, and paclitaxel that are used to treat various types of cancer. Many of these drugs have different mechanisms by which they cause cell death. New derivatives of FK866, considered to be one of the most potent anti-cancer drugs, have been developed through the inclusion of carboranes.7,8 These drugs have shown increased potency and antiproliferative activity against cancer cells in vitro through the use of various cell culture assays.9/11 The inhibitory concentrations on various cells lines were reported through the use of MTT colorimetric assays.12 Drug combinations were also performed and analyzed using CompuSyn to determine the existence of any synergistic effects.

In Situ HREM Observation of Phase Transformation Process in FePt and FePtCu Nanoparticles

2005 ◽  
Vol 907 ◽  
Author(s):  
Masatoshi Nakanishi ◽  
Gen-ichi Furusawa ◽  
Kokichi Waki ◽  
Yasushi Hattori ◽  
Takeo Kamino ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Single Crystal ◽  
Particle Formation ◽  
Cubic Phase ◽  
Fept Nanoparticles ◽  
Crystal Formation ◽  
Face Centered Cubic ◽  
Shaped Particle ◽  
Face Centered

AbstractThe processes of phase transformation in individual nanoparticles of FePt and FePtCu synthesized by the reverse micelle method, which are chemically homogeneous and monodisperse, have been investigated by an in-situ HREM observation in a FE-TEM. Polycrystalline FePt particles, initially of chemically disordered face-centered cubic phase (A1) were reconstructed into A1 single crystals between 25 °C and 650 °C, followed by phase transformation from A1 to chemically ordered face-centered tetragonal phase (L10) which began between 650 °C and 680 °C. The coalescence began concurrently with phase transformation, i. e., between 650 °C and 680 °C. They turned to be a round-shaped L10 particle between 680 °C and 720 °C. The single crystal formation, the phase transformation from A1 to L10, the coalescence and the round-shaped particle formation were also observed in the FePtCu nanoparticles. The temperatures of single crystal formation, phase transformation (and coalescence) and round-shaped particle formation of the FePtCu nanoparticles were between 25 °C and 500 °C, between 550 °C and 600 °C and between 600 °C and 650 °C, respectively. These temperatures were substantially lower than those for the FePt nanoparticles.

Synthesis of Monodisperse FePt Nanoparticles at a Low Temperature

2007 ◽  
Vol 124-126 ◽  
pp. 899-902
Author(s):  
Hui Ping Shao ◽  
Yu Qiang Huang ◽  
Hyo Sook Lee ◽  
Yong Jae Suh ◽  
Chong Oh Kim
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Thermal Annealing ◽  
Crystalline Structure ◽  
Fept Nanoparticles ◽  
Face Centered Cubic ◽  
Face Centered

Monodisperse FePt nanoparticles were synthesized by thermal decomposition of Fe(CO)5 and reduction of Pt(acac)2 at low temperature of 160–180 °C by using kerosene as a solvent. The average sizes of the synthesized particles ranged from 2.2 to 4.4 nm. Thermal annealing of the as-prepared FePt particles at 700 °C for 1 h transformed the crystalline structure of the particles from a disordered face-centered cubic to an ordered face-centered tetragonal. This change led to a significant increase in coercivity from 153.37 to 2273.22 Oe and in saturated magnetization from 26.86 to 41.21 emu/g.

Synthesis and characterization of L10 FePt nanoparticles from Pt–Fe3O4 core-shell nanoparticles

2005 ◽  
Vol 294 (2) ◽  
pp. e95-e98 ◽  
Author(s):  
V.K. Tzitzios ◽  
D. Petridis ◽  
I. Zafiropoulou ◽  
G. Hadjipanayis ◽  
D. Niarchos
Keyword(s):  
Synthesis And Characterization ◽  
Core Shell ◽  
Fept Nanoparticles ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles ◽  
Fe3o4 Core

Ferromagnetic resonance spectroscopy of CoFeZr-Al2O3 granular films containing “FeCo core – oxide shell” nanoparticles

2017 ◽  
Vol 421 ◽  
pp. 98-102 ◽  
Author(s):  
Tomasz N. Kołtunowicz ◽  
Pawel Zukowski ◽  
Julia Sidorenko ◽  
Vadim Bayev ◽  
Julia A. Fedotova ◽  
...  
Keyword(s):  
Ferromagnetic Resonance ◽  
Oxide Shell ◽  
Resonance Spectroscopy ◽  
Shell Nanoparticles ◽  
Granular Films
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