Effects of PS–PVP diblock copolymer topography on the magnetic properties of CoCrPt thin films

Jeong, Jong‐Ryul; Choi, Myung Chul; Kim, Mahn Won; Shin, Sung‐Chul

doi:10.1002/pssb.200304542

Cited by 6 publications

(5 citation statements)

References 15 publications

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“…The magnitude of the positive susceptibility for the Rh nanoparticle aggregates is somewhat larger than that for bulk Rh, which could result from the small size of the nanoparticles or from defects in the structure or surface of the nanoparticles. PVP generally does not have a significant influence on the magnetic properties of nanoparticles. , However, surface effects are not uncommon, and these can lead to enhanced moments 10 Field-cooled dc susceptibility data for (a) bulk Rh metal and (b) spherical Rh nanoparticle aggregates from 4 to 300 K at 1000 Oe.…”

Section: Resultsmentioning

confidence: 99%

Spontaneous Hierarchical Assembly of Rhodium Nanoparticles into Spherical Aggregates and Superlattices

et al. 2005

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Reduction of aqueous RhCl 3 with NaBH 4 in the presence of poly(vinyl pyrrolidone) (PVP) yields dense spherical nanostructures. The spherical aggregates, which generally have diameters between 10 and 100 nm, are built from smaller 1-3 nm Rh particles. The dense nanostructures are thermally stable beyond 100 °C, and they have a tendency to form ordered superstructures upon drying. Combining sodium n-dodecyl sulfate (SDS) with PVP modifies the size and morphology of the primary 1-3 nm particles, but does not change the spherical shape of the aggregates except at high concentrations of SDS. Smallangle X-ray scattering measurements show that the large aggregates are formed directly in solution from small Rh particles, consistent with TEM and AFM results. Magnetic measurements indicate that the Rh nanoparticle aggregates are Pauli paramagnetic.

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Section: Resultsmentioning

confidence: 99%

Spontaneous Hierarchical Assembly of Rhodium Nanoparticles into Spherical Aggregates and Superlattices

et al. 2005

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“…Earlier literature for PS-P4VP block copolymers in toluene suggests an aggregation number N of ~6 for block copolymers with a molecular weight of PS 21400 -P4VP 20700 . 6 The molecular weight utilized here is PS 20000 -P4VP 19000 which is very similar. Assuming an N of 6, there are ~1085 pyridine groups per micelle.…”

Section: Smentioning

confidence: 99%

Block Copolymer-Templated Chemistry on Si, Ge, InP, and GaAs Surfaces

2005

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Patterning of semiconductor surfaces is an area of intense interest, not only for technological applications, such as molecular electronics, sensing, cellular recognition, and others, but also for fundamental understanding of surface reactivity, general control over surface properties, and development of new surface reactivity. In this communication, we describe the use of self-assembling block copolymers to direct semiconductor surface chemistry in a spatially defined manner, on the nanoscale. The proof-of-principle class of reactions evaluated here is galvanic displacement, in which a metal ion, M+, is reduced to M0 by the semiconductor, including Si, Ge, InP, and GaAs. The block copolymer chosen has a polypyridine block which binds to the metal ions and brings them into close proximity with the surface, at which point they undergo reaction; the pattern of resulting surface chemistry, therefore, mirrors the nanoscale structure of the parent block copolymer. This chemistry has the added advantage of forming metal nanostructures that result in an alloy or intermetallic at the interface, leading to strongly bound metal nanoparticles that may have interesting electronic properties. This approach has been shown to be very general, functioning on a variety of semiconductor substrates for both silver and gold deposition, and is being extended to organic and inorganic reactions on a variety of conducting, semiconducting, and insulating substrates.

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“…44 Black et al 73 deposited 2 nm Ti/6 nm Co over a porous template made by removing PMMA cylinders from a PS-PMMA BCP with the cylinders perpendicular to the substrate. Jeong et al 74 deposited CoCr(18at%)Pt(14at%) films over a film of PS-P2VP micelles formed by dissolving the block copolymer in toluene (a good solvent only for the PS) then spin-coating the resulting micelles on a Si surface. The micelle array had period 40 nm and a height variation of 4 nm, so the overlying magnetic film had a significant roughness.…”

Section: Additive Patterning Methodsmentioning

confidence: 99%

“…74 The films appeared to be continuous but with significant roughness and local thickness variations, and had a higher coercivity and perpendicular anisotropy compared to a smooth film. The change in magnetic properties was attributed to surface roughness of the film, which reduced the demagnetizing factor and pinned domain wall motion.…”

Section: Antidot Arrays and Non-planar Filmsmentioning

confidence: 97%

Block Copolymer Lithography for Magnetic Device Fabrication

Cheng¹,

Ross²

2008

Series in Soft Condensed Matter

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Block copolymers have been used in a number of lithographic applications including the fabrication of magnetic nanostructures, which are of particular interest in data storage. This chapter reviews the materials and processing requirements for block copolymer lithography, and then describes pattern transfer from block copolymer films into magnetic materials using both additive and subtractive methods, and the magnetic properties of the resulting structures. To create structures with long-range order, templating of the block copolymer microphase separation is necessary, and the strategies for accomplishing this will be reviewed with emphasis on the use of topographically modulated templates. The chapter concludes with a summary and outlook for block copolymer patterning of nanomagnetic devices.

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Effects of PS–PVP diblock copolymer topography on the magnetic properties of CoCrPt thin films

Cited by 6 publications

References 15 publications

Spontaneous Hierarchical Assembly of Rhodium Nanoparticles into Spherical Aggregates and Superlattices

Spontaneous Hierarchical Assembly of Rhodium Nanoparticles into Spherical Aggregates and Superlattices

Block Copolymer-Templated Chemistry on Si, Ge, InP, and GaAs Surfaces

Block Copolymer Lithography for Magnetic Device Fabrication

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