Browsing Department of Physics by Author "Liu, J. Ping"
Now showing items 1-20 of 33
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Anisotropic nanostructured magnets by magnetic-field-assisted processing
Rong, Chuan-Bing; Nguyen, Van Vuong; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2010-04-15)It has been a great challenge to produce anisotropic nanocrystalline bulk magnets. In this paper, we report our recent work in preparing anisotropic bonded magnets consisting of SmCo5 nanocrystalline particles. The work ... -
Bimagnetic nanoparticles with enhanced exchange coupling and energy products
Nandwana, Vikas; Chaubey, Girija Shankar; Yano, Kazuaki; Rong, Chuan-Bing; Liu, J. Ping (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
Rong, Chuan-Bing; Nandwana, Vikas; Poudyal, Narayan; Liu, J. Ping; Kozlov, Mikhail E.; Baughman, Ray H.; Ding, Yong; Wang, Zhong Lin (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-based nanocomposite magnets with enhanced exchange coupling
Nandwana, Vikas; Liu, J. Ping; Poudyal, Narayan; Rong, Chuan-Bing; Kozlov, Mikhail E.; Baughman, Ray H.; Ding, Yong; Wang, Zhong Lin (AIP, 2007)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
Rong, Chuan-Bing; Nandwana, Vikas; Poudyal, Narayan; Liu, J. Ping; Saito, Tetsuji; Wu, Yaqiao; Kramer, Matthew J. (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 ... -
Bulk FePt/Fe3Pt nanocomposite magnets prepared by spark plasma sintering
Nandwana, Vikas; Rong, Chuan-Bing; Poudyal, Narayan; Liu, J. Ping; Saito, Tetsuji; Wu, Yaqiao; Kramer, Matthew J. (AIP, 2007)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
Rong, Chuan-Bing; Li, Yang; Liu, J. Ping (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?
Rong, Chuan-Bing; Liu, Yuzi; Liu, J. Ping (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 ... -
Effect of thermal fluctuations on the recoil loops of SmCo5[subscript]/Fe nanocomposite system
Rong, Chuan-Bing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-02-13)The correlation between the recoil loop openness and the activation volume has been studied for the SmCo5/α-Fe nanocomposite powder material prepared by mechanical alloying. The α-Fe phase content in the nanocomposite ... -
Effects of particle size and composition on coercivity of Sm–Co nanoparticles prepared by surfactant-assisted ball milling
Poudyal, Narayan; Rong, Chuan-Bing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2010-04-15)The correlation between the recoil loop openness and the activation volume has been studied for the SmCo5/α-Fe nanocomposite powder material prepared by mechanical alloying. The α-Fe phase content in the nanocomposite ... -
Fabrication of bulk nanocomposite magnets via severe plastic deformation and warm compaction,
Rong, Chuan-Bing; Zhang, Ying; Poudyal, Narayan; Xiong, Xiangyuan; Kramer, Matthew J.; Liu, J. Ping (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. ... -
Fabrication Of Superparamagnetic And Ferromagnetic Nanoparticles
Poudyal, Narayan (Physics, 2009-09-16)Monodisperse magnetic nanoparticles with controlled size and geometry have drawn great attention in the last decade for fundamental scientific studies and for their potential applications in advanced materials and devices ... -
Ferroelectric And Ferromagnetic Behavior Of Oxide Containing Thin Films
Choi, Hai InOxide materials are important due to their interesting physical properties for applications in future electronic devices. Thin film oxide materials show a variety of electric and magnetic properties such as ferroelectric, ... -
First-principles prediction of enhanced magnetic anisotropy in FeCo alloys
Wu, Dangxin; Zhang, Qiming; Liu, J. Ping; Yuan, Dingwang; Wu, Ruqian (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 ... -
Grain boundary contribution to recoil loop openness of exchange-coupled nanocrystalline magnets
Rong, Chuan-Bing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-04-29)It has been well known that recoil loop openness is related to soft-phase presence in exchange-coupled hard-soft nanocomposite magnets. Our study on recoil loop openness of exchange-coupled nanocrystalline magnets (both ... -
Hard magnetic FePt nanoparticles by salt-matrix annealing
Nandwana, Vikas; Li, Daren; Poudyal, Narayan; Jin, Zhiqiang; Elkins, Kevin Eugene; Liu, J. Ping (AIP, 2006)To transfer face-centered-cubic (fcc) FePt nanoparticles to the face-centered-tetragonal (fct) phase with high magnetic anisotropy, heat treatments are necessary. The heat treatments lead to agglomeration and sintering of ... -
High thermal stability of carbon-coated L10-FePt nanoparticles prepared by salt-matrix annealing
Nandwana, Vikas; Rong, Chuan-Bing; Poudyal, Narayan; Chaubey, Girija S.; Liu, Yuzi; Wu, Y.Q.; Kramer, M.J.; Kozlov, M.E.; Baughman, Ray H.; Liu, J. Ping (AIP, 2008)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 ... -
High thermal stability of carbon-coated L1[subscript]0-FePt nanoparticles prepared by salt-matrix annealing
Rong, Chuan-Bing; Poudyal, Narayan; Chuabey, Girija S.; Nandwana, Vikas; Liu, Yuzi; Wu, Y.Q.; Kramer, Matthew J.; Kozlov, Mikhail E.; Baughman, Ray H.; Liu, J. Ping (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)z high temperature magnets
Rong, Chuan-Bing; Shen, Bao-Gen; Zhang, Hong-Wei; Liu, J. Ping (AIP, 2006)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 ... -
Mechanism of the anomalous temperature dependence of coercivity in Sm(Co,Fe,Cu,Zr)[subscript]z high-temperature magnets
Rong, Chuan-Bing; Zhang, Hong-wei; Shen, Bao-gen; Liu, J. Ping (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 ...