Self-assembled ferrimagnet-polymer composites for magnetic recording media.
Summary of "Self-assembled ferrimagnet-polymer composites for magnetic recording media."
A self-assembled magnetic recording medium was created using colloidal ferrimagnetic building blocks. Monodisperse cobalt ferrite nanoparticles (CoFe(2)O(4)) were synthesized using solution-based methods and then stabilized in solution using the amphiphilic diblock copolymer, poly(acrylic acid)-b-poly(styrene) (PAA-PS). The acid groups of the acrylate block bound the polymer to the nanoparticle surface via multivalent interactions, while the styrene block afforded the magnetic nanoparticle-polymer complex solubility in organic solvents. Moreover, the diblock copolymer improved the colloidal stability of the ferrimagnetic CoFe(2)O(4) nanoparticles by reducing the strong interparticle magnetic interactions, which typically caused the ferrimagnetic nanoparticles to irreversibly aggregate. The nanoparticle-polymer complex was spin-coated onto a silicon substrate to afford self-organized thin film arrays, with the interparticle spacing determined by the molecular weight of the diblock copolymer. The thin film composite was also exposed to an external magnetic field while simultaneously heated above the glass transition temperature of poly(styrene) to allow the nanoparticles to physically rotate to align their easy axes with the direction of the magnetic field. In order to demonstrate that this self-assembled ferrimagnet-polymer composite was suitable as a magnetic recording media, read/write cycles were demonstrated using a contact magnetic tester. This work provides a simple route to synthesizing stabilized ferrimagnetic nanocrystals that are suitable for developing magnetic recording media.
Affiliation
IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120.
Journal Details
This article was published in the following journal.
Name: Nano letters
ISSN: 1530-6992
Pages: 3216-21
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20698640
- DOI: http://dx.doi.org/10.1021/nl1022749
Medical and Biotech [MESH] Definitions
Culture Media
Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.
Polyethyleneimine
Strongly cationic polymer that binds to certain proteins; used as a marker in immunology, to precipitate and purify enzymes and lipids. Synonyms: aziridine polymer; Epamine; Epomine; ethylenimine polymer; Montrek; PEI; Polymin(e).
Agar
A complex sulfated polymer of galactose units, extracted from Gelidium cartilagineum, Gracilaria confervoides, and related red algae. It is used as a gel in the preparation of solid culture media for microorganisms, as a bulk laxative, in making emulsions, and as a supporting medium for immunodiffusion and immunoelectrophoresis.
Culture Media, Conditioned
Culture media containing biologically active components obtained from previously cultured cells or tissues that have released into the media substances affecting certain cell functions (e.g., growth, lysis).
Communications Media
The means of interchanging or transmitting and receiving information. Historically the media were written: books, journals, newspapers, and other publications; in the modern age the media include, in addition, radio, television, computers, and information networks.
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