Fabrication of two-dimensional assembly of L1FePt nanoparticles

Miyazaki, Tatsuya; Okamoto, Satoshi; Kitakami, Osamu; Shimada, Yutaka

doi:10.1063/1.1558053

Cited by 6 publications

(3 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This unexpected structure appears using vapour phase deposition techniques with a low substrate temperature, because the growth kinetics of the particles is faster than the ordering kinetics. The ordering mechanisms require a post-synthesis annealing over 600°C [12]. After a thermal annealing of 1 hour at 700°C, the particles obtained with a 1 nm nominal thickness have a mean size of 3 nm whereas the ones obtained with 2 nm nominal thickness have a mean size of 5 nm.…”

Section: Results On Copt Nanoparticlesmentioning

confidence: 99%

STEM nanodiffraction technique for structural analysis of CoPt nanoparticles

et al. 2008

View full text Add to dashboard Cite

Studying the structure of nanoparticles as a function of their size requires a correlation between the image and the diffraction pattern of single nanoparticles. Nanobeam diffraction technique is generally used but requires long and tedious TEM investigations, particularly when nanoparticles are randomly oriented on an amorphous substrate. We bring a new development to this structural study by controlling the nanoprobe of the Bright and Dark Field STEM (BF/DF STEM) modes of the TEM. The particularity of our experiment is to make the STEM nanoprobe parallel (probe size 1 nm and convergence angle <1 mrad) using a fine tuning of the focal lengths of the microscope illumination lenses. The accurate control of the beam position offered by this technique allowed us to obtain diffraction patterns of many single nanoparticles selected in the digital STEM image. By means of this technique, we demonstrate size effects on the order-disorder transition temperature in CoPt nanoparticles when their size is smaller than 3 nm.

show abstract

Section: Results On Copt Nanoparticlesmentioning

confidence: 99%

STEM nanodiffraction technique for structural analysis of CoPt nanoparticles

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Epitaxial growth on single-crystalline substrates, such as MgO, successfully realized c-axis oriented fct-FePt nanoparticles. [3][4][5][6] However, this approach is not suitable for practical perpendicular recording media because an FePt recording layer should be formed on a poly-crystalline underlayer, such as the soft magnetic underlayer. Selfassembly of chemically synthesized magnetic nanoparticles [7][8][9] realized well-isolated structures, so called selfordered magnetic array (SOMA).…”

Section: Introductionmentioning

confidence: 99%

c-Axis Oriented Face-Centered-Tetragonal-FePt Nanoparticle Monolayer Formed on a Polycrystalline TiN Seed Layer

Noda

Tsuji

Sugiyama

et al. 2005

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

c-Axis oriented face-centered-tetragonal (fct)-FePt magnetic nanoparticles are a promising candidate for high density perpendicular magnetic recording media. In this study, TiN was investigated as a seed layer to achieve c-axis orientation of fct-FePt nanoparticles. First, a (200)-oriented, polycrystalline TiN layer with grain size around 10 nm was prepared by reactive sputter-deposition at 873 K on SiO2, and then FePt was sputter-deposited at 973 K on it. Both in-plane and out-of-plane X-ray diffraction revealed that FePt had fct structure with c-axis orientation. Plan-view field emission scanning electron microscopy showed that FePt formed well-isolated nanoparticles. The particle diameter increased with increasing nominal thickness of FePt, and it was similar to the size of the TiN grains when nominal thickness was 1.4 nm. Cross-sectional transmission electron microscope images indicated that single FePt nanoparticles grew on single TiN grains, namely, one nanoparticle per grain, with an epitaxial relationship. Superconducting quantum inference device measurement at 300 K revealed that the FePt nanoparticles had coercivity of 6.2 and 0.8 kOe for the out-of-plane and in-plane directions, respectively. The FePt nanoparticle monolayer sputter-deposited on polycrystalline TiN seed layer is a promising candidate for perpendicular magnetic recording media.

show abstract

“…From these viewpoints, many studies on the preparation of granular films, in which FePt nano-clusters are dispersed in nonmagnetic matrix, have been carried out in recent years. [3][4][5][6] Bian et al successfully prepared FePt nanoparticles around 10 nm diameter by vacuum successive deposition technique of Pt, Fe and Al 2 O 3 on a (001) surface of sodium chloride, however L1 0 -FePt was formed with three kinds of variant, one of which has c-axis perpendicular to film surface after annealing at 873 K. 3) Other studies also needed high temperature for forming L1 0 phase. For the practical application, process temperature should be suppressed lower and a few researches have been reported from this viewpoint.…”

Section: Introductionmentioning

confidence: 99%

HRTEM and EELS Studies of L1<SUB>0</SUB>-Ordered FePt nano-Clusters on MgO Films Prepared Below 673 K

2004

View full text Add to dashboard Cite

Three kinds of FePt-MgO granular films were prepared by a vacuum successive deposition of MgO, Pt, Fe and MgO on a cleaved surface of sodium chloride below 673 K. Their microstructures, electronic structures and magnetic properties were studied by high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS) and measurement with a superconducting quantum interference device (SQUID) magnetometer. The TEM observations and selected area electron diffraction patterns revealed that the samples mainly consist of few nm-sized FePt clusters embedded in MgO films with L1 0 -ordered structure and c-axis perpendicular to the film surface. Size effect on the stability of L1 0 phase in the FePt nano-clusters was directly observed in [MgO/Fe(0.38 nm)/Pt(0.30 nm)/MgO] and the critical size of the transition from L1 0 to A1 phase was estimated as around 2 nm, that can be considered as smaller than effective size for the transition from ferromagnetism to superparamagnetism. Coercivity of [MgO/Fe(1.0 nm)/Pt(0.8 nm)/MgO] was 1:2 Â 10 5 A/m. The Fe-L 2;3 white-line ratios of the present samples measured by EELS were about 4.0, independently on the incident direction of electron beam. The higher white-line ratio may be attributed to their high-spin state by a change of 3d-band structure owing to the hybridization of d-bands between Fe and Pt atoms.

show abstract

Fabrication of two-dimensional assembly of L1FePt nanoparticles

Cited by 6 publications

References 7 publications

STEM nanodiffraction technique for structural analysis of CoPt nanoparticles

STEM nanodiffraction technique for structural analysis of CoPt nanoparticles

c-Axis Oriented Face-Centered-Tetragonal-FePt Nanoparticle Monolayer Formed on a Polycrystalline TiN Seed Layer

HRTEM and EELS Studies of L1<SUB>0</SUB>-Ordered FePt nano-Clusters on MgO Films Prepared Below 673 K

Contact Info

Product

Resources

About