Effect of Growth Temperature on the Shape and Crystallinity of Chemically Produced FePt Nanoparticles

Hachisu, Takuma; Yotsumoto, Takahiro; Sugiyama, Atsushi; Iida, Hironori; Nakanishi, Tetsuya; Asahi, Toru; Osaka, Tetsuya

doi:10.1246/cl.2008.840

Cited by 11 publications

(10 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3a, which is similar to the results of our previous studies. 20 Based on Chen et al's previous paper, 3 the ͑100͒-textured nanoparticles exhibit a cubic shape. The average nanocube composition was confirmed to be Fe 52 Pt 48 from the energy-dispersive X-ray results.…”

Section: Resultsmentioning

confidence: 99%

“…Previously, we succeeded in fabricating cubic FePt nanoparticles ͑FePt nanocubes͒ with partial L1 0 phases by controlling the growth temperature during chemical synthesis. 20 Self-assembled FePt nanocubes have a ͑100͒ texture on a Cu grid with a carbon-supporting film. This shape-controlled synthesis and self-assembly offers a promising approach to fabricate magnetically aligned FePt nanocrystal arrays for a wide range of applications.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Arrangement of FePt Nanocubes Utilizing Chemical Binding Selectivity

Hachisu

Sato²,

Sugiyama³

et al. 2010

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

This study on future ultrahigh density magnetic recording devices aims to develop a technique for arranging FePt nanocubes on a substrate by using organosilane as an interlayer. An array of FePt nanocubes was formed by chemical synthesis, utilizing the Pt-S binding between the SH functional group in ͑3-mercaptopropyl͒trimethoxysilane and Pt in the FePt nanocubes. The morphology of the FePt nanocube array on the substrate was characterized using atomic force microscopy and plan-view scanning electron microscopy, which revealed that the array was a monolayer. After SiO 2 was coated by chemical vapor deposition as a protective layer for sintering prevention, annealing was carried out at 900°C for 3 h in a reducing atmosphere to transform the crystal structure of the FePt nanocubes to the L1 0 phase. X-ray diffraction results revealed that the annealed FePt nanocube array had a FePt͑110͒ orientation and L1 0 phases such as ͑001͒ and ͑110͒. The Pt-S binding did not obstruct the L1 0 ordering of FePt. Consequently, a method for arranging nanoparticles by using the organic molecules with functional groups that can interact with nanoparticle selectivity as an interlayer can be applied as a formation technique for arranging a wide range of nanoparticles. L1 0 -FePt alloys have a very high uniaxial magnetic crystalline anisotropy energy ͑K u = 7 ϫ 10 7 erg/cm 3 ͒. Because the superparamagnetic fluctuation of room-temperature magnetization can be suppressed even for grains with a diameter of 3.0 nm, the appropriate arrangement of FePt nanoparticles composed of one recording bit ϫ one particle is a promising candidate for next-generation-type ultrahigh density magnetic recording media with capacities of Ͼ10 Tbit in. −2 . Since the preparation of monodisperse FePt nanoparticles by chemical synthesis was reported by Sun et al., 1-4 many researchers have paid attention to such nanoparticles for a wide range of applications including magnetic recording media, 5-8 ferrofluids, 9-11 magnetic hyperthermia, 12 magnetic resonance imaging contrast agents, 13 magnetic cell separation, 14 and environmental remediation. 15 Techniques for arranging nanoparticles and controlling the magnetic easy axis in two dimensions ͑2D͒ are very important for the development of ultrahigh density magnetic recording media. Some methods of 2D arrangement such as self-organization and Langmuir-Blodgett ͑LB͒ 16-19 have been reported. It is difficult to use the self-assembly and LB techniques for controlling better organized monolayers on a substrate. This study aims to develop a technique for arranging FePt nanoparticles on a substrate by using organosilane as an interlayer. Previously, we succeeded in fabricating cubic FePt nanoparticles ͑FePt nanocubes͒ with partial L1 0 phases by controlling the growth temperature during chemical synthesis. 20 Self-assembled FePt nanocubes have a ͑100͒ texture on a Cu grid with a carbon-supporting film. This shape-controlled synthesis and self-assembly offers a promising approach to fabricate magnetically aligned FePt na...

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Arrangement of FePt Nanocubes Utilizing Chemical Binding Selectivity

Hachisu

Sato²,

Sugiyama³

et al. 2010

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Both OAc and OAm were used as nanoparticle surfactants. As in previous studies, 13,14 the synthesis was performed at 295…”

Section: Methodsmentioning

confidence: 99%

“…Both OAc and OAm were used as nanoparticle surfactants. As in previous studies, 13,14 the synthesis was performed at 295 • C for 2 h in a nitrogen gas atmosphere with no moisture. After cooling the solution to room temperature, a black product was centrifuged by adding ethanol to the solution, and the particles were then redispersed in toluene (5, 10, and 20 g•dm −3 of FePt nanoparticles).…”

Section: Methodsmentioning

confidence: 99%

Promotion of Self-Assembly Patterning of FePt Nanoparticles by Tuning the Concentration of Oleylamine/Oleic Acid Surfactants in a Coating Solution

Yoshiki

Hachisu

Suguru

et al. 2016

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

To provide a bit-patterned perpendicular magnetic recording medium consisting of an array of FePt magnetic nanoparticles, the effect of the total dispersant concentrations of oleylamine and oleic acid in a FePt-nanoparticle/toluene coating solution on a selfassembled nanoparticle array with a long-range periodicity on a flat SiO 2 /Si substrate and two patterned substrates, respectively, was examined. At a surfactant concentration greater than 0.8 vol%, FePt nanoparticles with an average size of 4.4 nm were arrayed in a two-dimensional and hexagonal-close-packed ordered array with 8.3-nm pitches on the flat surface. Self-assembled nanoparticles were arrayed on the bottom surface of the patterned trench, the array exhibited a hexagonal-close-packed structure. Furthermore the line defects in the arrays are caused by the waviness of the trench walls, and the surface roughness. A hard disk drive (HDD) using a perpendicular magnetic recording system has been continuously developed, and the current areal recording density has achieved 1 Tbit·in −2 , which corresponds to one bit size smaller than 25 × 25 nm 2 . 1 However, a greater areal density is required to handle big data and reduce the electric power consumption by replacing current products with high-performance HDDs. Bit-patterned media (BPM) consisting of isolated magnetic dots are a promising future magnetic recording technology, and the integration of BPM into a heat-assisted magnetic recording (HAMR) or microwave-assisted magnetic recording (MAMR) system is expected to achieve a higher recording density.2 However, the fabrication of bit patterns with a pitch of less than 20 nm in the circumferential direction on a commercial 2.5-or 3.5-inch disk is a major challenge for producing BPM. Electron-beam lithography, nanoimprint lithography, and extreme ultraviolet lithography can usually create fine patterns on a chip with a size on the order of several square centimeters. Such lithographic techniques began with the ultra-large scale integration (ULSI) of integrated circuits (ICs). These techniques are cost effective for ULSI manufacturing but problematic for magnetic memory media owing to the cost (deep-UV and E-beam lithography) or manufacturability (nanoimprinting).On the contrary, nano-patterning using self-assembly has also attracted much attention as a simple and cost-effective method. For example, the self-organization of block copolymers 3,4 and the self-assembly of magnetic nanoparticles 5 have been reported. For nanoparticle fabrication, many methods for synthesizing fine magnetic nanoparticles have been reported, 5 and the current focus has shifted to a method of fabricating a two-or three-dimensional nanoparticle array on a substrate with a size of more than 100 nm. The LangmuirBlodgett technique, 6,7 doctor-blade coating, 8,9 and spin-coating 10,11 have been proposed as methods of fabricating nanoparticles in an ordered array utilizing self-assembly. As in previous study, 12 a picoliter-regulated pipette was used as an apparatus for coating synthesiz...

show abstract

“…5) Superparamagnetic fluctuation of roomtemperature magnetization can thus be suppressed even for particles with diameters ranging from 2.7-3.0 nm. 6) FePt nanoparticles fabricated by chemical synthesis methods are low in cost and easy to control. An American researcher, Bhargava reported the luminescence of ZnS nanophosphor in an international conference of luminescence in 1994.…”

Section: Introductionmentioning

confidence: 99%

Hybridization of FePt/ZnS Nanocore-Shell Structure with DNAs of Different Sequences

Chang

2010

Mater. Trans.

View full text Add to dashboard Cite

This study attempts to develop a nanocore-shell structure with photomagnetic nature. The structure is then allowed undergo conjugation reaction with the DNAs of different sequences so that it can be applied to target-based drug therapy and biomedical-related areas. First of all, iron platinum (FePt) magnetic nanofluid with an average particle size of 2-3 nm is prepared by a chemical method. After that, zinc sulfide with a fluorescent nature is used to modify the surface of the nanoparticles so as to form a core-shell structure. The shell thickness in this kind of coreshell structure can be controlled at 5-10 nm by a fabrication process. The FePt nanoparticles being modified by zinc sulfide not only can enhance the dispersed suspension of nanoparticles, but also have good optical nature. The prepared nanocore-shell structured particles are conjugated with two groups of DNA of different sequences respectively. Nanoparticles before and after being conjugated and the structure of DNA are not deteriorated or altered because of the principle of positive and negative charges attraction. Conjugation efficiency is 64% and 77% respectively. A bridge DNA and two groups of DNA of different sequences are conjugated. Moreover, the occurrence of hybridization is proven through the analyses of the UV-vis spectrum. Analyses by fluorescence spectrometer show that the luminescence for modified ZnS and nanoparticles after hybridization respectively increases significantly.

show abstract

Effect of Growth Temperature on the Shape and Crystallinity of Chemically Produced FePt Nanoparticles

Cited by 11 publications

References 7 publications

Arrangement of FePt Nanocubes Utilizing Chemical Binding Selectivity

Arrangement of FePt Nanocubes Utilizing Chemical Binding Selectivity

Promotion of Self-Assembly Patterning of FePt Nanoparticles by Tuning the Concentration of Oleylamine/Oleic Acid Surfactants in a Coating Solution

Hybridization of FePt/ZnS Nanocore-Shell Structure with DNAs of Different Sequences

Contact Info

Product

Resources

About