Browsing J. Ping Liu, Ph.D. by Subject "Iron alloys"
Now showing items 1-15 of 15
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Bimagnetic nanoparticles with enhanced exchange coupling and energy products
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-01-06)Bimagnetic FePt/Fe3O4 nanoparticles with core/shell or heterodimer structure have been prepared using a sequential synthetic method. The dimension of both FePt and Fe3O4 was tuned by varying the synthesis parameters. The ... -
Bulk FePt-based nanocomposite magnets with enhanced exchange coupling
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-07-23)High density bulk FePt/Fe3Pt nanocomposite magnets have been prepared by high-pressure warm compaction of chemically synthesized FePt and Fe3O4 nanoparticles. It is found that the density increases with the compaction ... -
Bulk FePt/Fe3Pt nanocomposite magnets prepared by spark plasma sintering
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-04-27)FePt/Fe3Pt bulk nanocomposite magnets have been prepared by the spark plasma sintering of chemically synthesized FePt and Fe3O4 nanoparticles under 100 MPa at 400–600 °C. It was found that the phase transition of the FePt ... -
Curie temperatures of annealed FePt nanoparticle systems
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-03-28)The chemically synthesized FexPt100-x nanoparticles with controlled compositions were annealed to transfer the disordered face-centered-cubic structure to the ordered structure. It was found that the L10 FePt structure can ... -
Do thermal fluctuations influence the recoil loops of nanocomposite magnets?
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2008-07-11)An exchange-coupled FePt/Fe3Pt nanocomposite system with well defined hard/soft two-phase morphology was prepared by reducing chemically synthesized FePt/Fe3O4 bimagnetic nanoparticles. It was interesting to observe that ... -
Fabrication of bulk nanocomposite magnets via severe plastic deformation and warm compaction,
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2010-03-10)We demonstrate that a SmCo/FeCo based hard/soft nanocomposite material can be fabricated by distributing the soft magnetic α-Fe phase particles homogeneously in a hard magnetic SmCo phase through severe plastic deformation. ... -
First-principles prediction of enhanced magnetic anisotropy in FeCo alloys
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2008-02-04)The structural, electronic, and magnetic properties of FeCo alloys were studied by first-principles calculations. It has been found that the alloys prefer chemically noncubic geometries in a wide composition range. This ... -
High thermal stability of carbon-coated L1[subscript]0-FePt nanoparticles prepared by salt-matrix annealing
(Institute of Applied PhysicsDepartment of Physics, The University of Texas at Arlington, 2008-02-08)Monodisperse L10-FePt nanoparticles with size ranging from 3 to 8 nm were prepared by the salt-matrix annealing method. It was observed that the annealed particles have high thermal stability—no sintering occurred even ... -
Mechanism of the anomalous temperature dependence of coercivity in Sm(Co,Fe,Cu,Zr)[subscript]z high-temperature magnets
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2006-01-24)Coercivity mechanism of the precipitation-hardened Sm(Co,Fe,Cu,Zr)z high-temperature magnets was found to vary with temperature by measurements of reversible magnetization. The magnetization reversal is mainly controlled ... -
Observation of L1[subscript]0-like chemical ordering in a decahedral FePt nanoparticle by C[subscript]s-corrected high resolution transmission electron microscopy
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-03-09)The state of the chemical ordering in a decahedral FePt nanoparticle was studied using aberration corrected high resolution transmission electron microscopy. With the reduced image delocalization effect as a result of ... -
Phase Transformation and Magnetic Hardening in Isolated FePt Nanoparticles
(IEEEDepartment of Physics, The University of Texas at Arlington, 2009-03-31)Isolated monodisperse L1[subscript]0 FePt nanoparticles coated by carbon were obtained by adding enough surfactants that decomposed into carbon after the chemical synthesis and postannealing of the A1 FePt nanoparticles. ... -
Rapid thermal annealing of FePt nanoparticles
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2008-07-11)We report a systematic study on rapid thermal annealing (RTA) of FePt nanoparticles. FePt particles with an average size of 8 nm were synthesized by a chemical solution method, and then annealed using RTA and conventional ... -
Shape control of FePt nanocrystals
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-04-06): FePt nanocrystals were prepared by simultaneous reduction of platinum acetylacetonate and thermal decomposition of iron pentacarbonyl in properly chosen solvents/surfactants. A variety of FePt nanocrystals, including ... -
Structural phase transition and ferromagnetism in monodisperse 3 nm FePt particles
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-08-30)FePt nanoparticles with a size of 3 nm and thermally stable room-temperature ferromagnetism are investigated. The monodisperse nanoparticles were prepared by chemical synthesis and a salt-matrix annealing technique. ... -
Temperature- and magnetic-field-induced phase transitions in Fe-rich FePt alloys
(American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-06-01)Structural and magnetic properties of the FexPt100-x (x=78–88) alloys have been investigated. It is found that for all of the investigated compositions, a phase transition occurs from the disordered γ phase to the ordered ...