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Synthesis and Characteristics of FePt Nanoparticle Films Under In Situ-Applied Magnetic Field.

Qian X, Gao MY, Li AD, Zhou XY, Liu XJ, Cao YQ, Li C, Wu D - Nanoscale Res Lett (2016)

Bottom Line: The effect of in situ-applied magnetic field on the structure, morphology, and magnetic properties of FePt nanoparticle films was characterized.It is found that the applied magnetic field during the chemical synthesis of FePt nanoparticles plays a key role in the crystallinity and magnetic property of FePt nanoparticle films.The applied magnetic field during the synthesis of FePt nanoparticles not only significantly improves the nanoparticles' c-axis preferred orientation but also benefits the phase transition of FePt nanoparticles from face-centered cubic to face-centered tetragonal structure during the annealing process.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, People's Republic of China.

ABSTRACT
In situ external magnetic field was applied during the synthesis of FePt nanoparticles via a chemical solution method. FePt nanoparticle films were prepared on Si by a drop-coating method with and without a magnetic field. Annealing at 700 °C in reductive atmosphere was explored to obtain ferromagnetic FePt L10 phase. The effect of in situ-applied magnetic field on the structure, morphology, and magnetic properties of FePt nanoparticle films was characterized. It is found that the applied magnetic field during the chemical synthesis of FePt nanoparticles plays a key role in the crystallinity and magnetic property of FePt nanoparticle films. As-synthesized FePt nanoparticles under the magnetic field are monodispersed and can be self-assembled over a larger area by a dropping method. The applied magnetic field during the synthesis of FePt nanoparticles not only significantly improves the nanoparticles' c-axis preferred orientation but also benefits the phase transition of FePt nanoparticles from face-centered cubic to face-centered tetragonal structure during the annealing process. The FePt nanoparticle films derived under magnetic field also show some magnetic anisotropy.

No MeSH data available.


The grain morphology and size distribution of FePt nanoparticles. The TEM images of FePt nanoparticles synthesized with (a) and without (b) in situ-applied magnetic field. c The particle size distribution curve for as-prepared FePt nanoparticles under magnetic field from Fig. 3b
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Fig3: The grain morphology and size distribution of FePt nanoparticles. The TEM images of FePt nanoparticles synthesized with (a) and without (b) in situ-applied magnetic field. c The particle size distribution curve for as-prepared FePt nanoparticles under magnetic field from Fig. 3b

Mentions: As-synthesized FePt nanoparticles with and without an applied in situ magnetic field are both spherical shapes, as shown in Fig. 3a, b. The particles have an average size of 4.8 nm with better monodispersibility, measured from the TEM images, which is similar to the calculated value of ~4.1 nm from the XRD patterns using the Scherrer equation. The measured particle sizes from more than 100 FePt particles from the TEM image of Fig. 3b are fitted into the Gaussian curves (dashed line, Fig. 3c), and the calculated standard deviation is 0.6 nm. And a typical hexagonal close-packed structure can be recognized in Fig. 3a, b, indicating the FePt nanoparticles can keep their monodispersity with a better self-assembly pattern even if synthesized under in situ magnetic field. An analysis by EDS attached to SEM records the measured average Fe:Pt ratios of 50.9:49.1 and 52.8:47.2 for FePt nanoparticles with and without an applied magnetic field, respectively. Both are close to 1:1, suggesting that in situ-applied magnetic field during chemical synthesis has no obvious impact on the chemical composition of FePt nanoparticles. Some literature has reported that when the Fe:Pt ratio is represented by FexPt100 − x (40 ≤ x ≤ 60), nanoparticles can be transformed to ferromagnetic fct structure without the secondary phase such as Pt3Fe or Fe3Pt [39, 40].Fig. 3


Synthesis and Characteristics of FePt Nanoparticle Films Under In Situ-Applied Magnetic Field.

Qian X, Gao MY, Li AD, Zhou XY, Liu XJ, Cao YQ, Li C, Wu D - Nanoscale Res Lett (2016)

The grain morphology and size distribution of FePt nanoparticles. The TEM images of FePt nanoparticles synthesized with (a) and without (b) in situ-applied magnetic field. c The particle size distribution curve for as-prepared FePt nanoparticles under magnetic field from Fig. 3b
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig3: The grain morphology and size distribution of FePt nanoparticles. The TEM images of FePt nanoparticles synthesized with (a) and without (b) in situ-applied magnetic field. c The particle size distribution curve for as-prepared FePt nanoparticles under magnetic field from Fig. 3b
Mentions: As-synthesized FePt nanoparticles with and without an applied in situ magnetic field are both spherical shapes, as shown in Fig. 3a, b. The particles have an average size of 4.8 nm with better monodispersibility, measured from the TEM images, which is similar to the calculated value of ~4.1 nm from the XRD patterns using the Scherrer equation. The measured particle sizes from more than 100 FePt particles from the TEM image of Fig. 3b are fitted into the Gaussian curves (dashed line, Fig. 3c), and the calculated standard deviation is 0.6 nm. And a typical hexagonal close-packed structure can be recognized in Fig. 3a, b, indicating the FePt nanoparticles can keep their monodispersity with a better self-assembly pattern even if synthesized under in situ magnetic field. An analysis by EDS attached to SEM records the measured average Fe:Pt ratios of 50.9:49.1 and 52.8:47.2 for FePt nanoparticles with and without an applied magnetic field, respectively. Both are close to 1:1, suggesting that in situ-applied magnetic field during chemical synthesis has no obvious impact on the chemical composition of FePt nanoparticles. Some literature has reported that when the Fe:Pt ratio is represented by FexPt100 − x (40 ≤ x ≤ 60), nanoparticles can be transformed to ferromagnetic fct structure without the secondary phase such as Pt3Fe or Fe3Pt [39, 40].Fig. 3

Bottom Line: The effect of in situ-applied magnetic field on the structure, morphology, and magnetic properties of FePt nanoparticle films was characterized.It is found that the applied magnetic field during the chemical synthesis of FePt nanoparticles plays a key role in the crystallinity and magnetic property of FePt nanoparticle films.The applied magnetic field during the synthesis of FePt nanoparticles not only significantly improves the nanoparticles' c-axis preferred orientation but also benefits the phase transition of FePt nanoparticles from face-centered cubic to face-centered tetragonal structure during the annealing process.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, People's Republic of China.

ABSTRACT
In situ external magnetic field was applied during the synthesis of FePt nanoparticles via a chemical solution method. FePt nanoparticle films were prepared on Si by a drop-coating method with and without a magnetic field. Annealing at 700 °C in reductive atmosphere was explored to obtain ferromagnetic FePt L10 phase. The effect of in situ-applied magnetic field on the structure, morphology, and magnetic properties of FePt nanoparticle films was characterized. It is found that the applied magnetic field during the chemical synthesis of FePt nanoparticles plays a key role in the crystallinity and magnetic property of FePt nanoparticle films. As-synthesized FePt nanoparticles under the magnetic field are monodispersed and can be self-assembled over a larger area by a dropping method. The applied magnetic field during the synthesis of FePt nanoparticles not only significantly improves the nanoparticles' c-axis preferred orientation but also benefits the phase transition of FePt nanoparticles from face-centered cubic to face-centered tetragonal structure during the annealing process. The FePt nanoparticle films derived under magnetic field also show some magnetic anisotropy.

No MeSH data available.