International Business Machines Corporation

Leland Stanford Junior University

Louisiana Tech University

Shouheng Sun

Christopher Bruce Murray

Stephen McConnell Gates

David William Abraham

Charles Thomas Black

Philip Louis Trouilloud

Roger Hilsen Koch

Snorri Thorgeir Ingvarsson

Hendrik F Hamann

Dieter Klaus Weller

Shan X Wang

Heng Yu

John E E Baglin

Simone Anders

Hao Zeng

Magnetic materials and uses thereof are provided. In one aspect, a magnetic film is provided. The magnetic film comprises superparamagnetic particles on at least one surface thereof. The magnetic film may be patterned and may comprise a ferromagnetic material. The superparamagnetic particles may be coated with a non-magnetic polymer and/or embedded in a non-magnetic host material. The magnetic film may have increased damping and/or decreased coercivity.

Magnetic materials having superparamagnetic particles

Dumbbell-shaped or flower-shaped nanoparticles and a process of forming the same, wherein the process comprises forming a mixture of a nanoparticle with a precursor in a first solvent, wherein the nanoparticle comprises a hydrophobic outer coating; heating the mixture; cooling the mixture to room temperature; modifying the hydrophobic outer coating into a hydrophilic outer coating; precipitating a solid product from the mixture, and dispersing the product in a second solvent. The nanoparticles comprise any of a semiconducting, magnetic, and noble metallic material, wherein the nanoparticles comprise a first portion comprising any of PbSe, PbS, CdSe, CdS, ZnS, Au, Ag, Pd, and Pt, and wherein the precursor comprises any of a cationic, neutral or particulate Au, Ag, Pd, Pt, or transition metal (Fe, Co, Ni) precursors of Fe(CO), Co(CO), Ni(CO)or their analogues. The first and second solvents comprise any of alkanes, arenes, ethers, nitrites, ketones, and chlorinated hydrocarbons.

Dumbbell-like nanoparticles and a process of forming the same

A method and structure for making magnetite nanoparticle materials by mixing iron salt with alcohol, carboxylic acid and amine in an organic solvent and heating the mixture to 200-360&#xb0; C. is described. The size of the particles can be controlled either by changing the iron salt to acid/amine ratio or by coating small nanoparticles with more iron oxide. Magnetite nanoparticles in the size ranging from 2 nm to 20 nm with a narrow size distribution are obtained with the invention.

Process of making metal containing iron oxide and iron sulfide based nanoparticle materials

A method and structure for making magnetite nanoparticle materials by mixing iron salt with alcohol, carboxylic acid and amine in an organic solvent and heating the mixture to 200&#x2013;360 C is described. The size of the particles can be controlled either by changing the iron salt to acid/amine ratio or by coating small nanoparticles with more iron oxide. Magnetite nanoparticles in the size ranging from 2 nm to 20 nm with a narrow size distribution are obtained with the invention. The invention can be readily extended to other iron oxide based nanoparticle materials, including MFeO(M=Co, Ni, Cu, Zn, Cr, Ti, Ba, Mg) nanomaterials, and iron oxide coated nanoparticle materials. The invention also leads to the synthesis of iron sulfide based nanoparticle materials by replacing alcohol with thiol in the reaction mixture. The magnetite nanoparticles can be oxidized to &#x3b3;-FeO, or &#x3b1;-FeO, or can be reduced to bcc-Fe nanoparticles, while iron oxide based materials can be used to make binary iron based metallic nanoparticles, such as CoFe, NiFe, and FeCoSmx nanoparticles.

A process of forming a hard-soft phase, exchange-coupled, magnetic nanocomposite includes forming a dispersion of magnetic nanoparticles, separating the magnetic nanoparticles from a solvent of the dispersion so as to allow self-assembly of the magnetic nanoparticles, and removing a coating from the nanoparticles, which are disposed in a self-assembled, locally-ordered nanostructure.

Process of forming magnetic nanocomposites via nanoparticle self-assembly

A method and structure for making magnetite nanoparticle materials by mixing iron salt with alcohol, carboxylic acid and amine in an organic solvent and heating the mixture to 200&#x2013;360 C is described. The size of the particles can be controlled either by changing the iron salt to acid/amine ratio or by coating small nanoparticles with more iron oxide. Magnetite nanoparticles in the size ranging from 2 nm to 20 nm with a narrow size distribution are obtained with the invention. The invention can be readily extended to other iron oxide based nanoparticle materials, including M FeO(M=Co, Ni, Cu, Zn, Cr, Ti, Ba, Mg) nanomaterials, and iron oxide coated nanoparticle materials. The invention also leads to the synthesis of iron sulfide based nanoparticle materials by replacing alcohol with thiol in the reaction mixture. The magnetite nanoparticles can be oxidized to &#x3b3;-FeO, or &#x3b1;-FeO, or can be reduced to bcc-Fe nanoparticles, while iron oxide based materials can be used to make binary iron based metallic nanoparticles, such as CoFe, NiFe, and FeCoSmx nanoparticles.

Synthesis of magnetite nanoparticles and the process of forming Fe-based nanomaterials

A method and related apparatus to link and/or pattern self-assembled first objects to a second object. Each of the first object (e.g., a nanoparticle) can be embedded in a mobile binder (i.e., a stabilizer). The invention applies energy to the first object and stabilizer, links this first object to the second object, and provides a controlled linkage of the first object with respect to the second object. Applying this procedure to many such objects results in a larger a real arrangement of these linked objects. An appropriate solvent may be used to remove non-linked objects, yielding a patterned array. Thermal annealing can be applied to control the physical and chemical properties of the array.

Method and apparatus for linking and/or patterning self-assembled objects

A method and structure that forms a multilayer nanoparticle thin film assembly begins by functionalizing a substrate with functional molecules. Next, the invention replaces a stabilizer on a bottom surface of the first nanoparticles with the functional molecules via surface ligand exchange to make a first nanoparticle layer on the substrate. The invention then replaces the stabilizer on a top surface of the first nanoparticle layer with functional molecules via surface ligand exchange. The invention replaces the stabilizer on a bottom surface of the second nanoparticles with the functional molecules via surface ligand exchange to make a second nanoparticle layer on the first nanoparticle layer. Lastly, the invention repeats the previous steps and forms additional nanoparticle layers.

Process of forming a multilayer nanoparticle-containing thin film self-assembly

A method for making nanoparticles via metal salt reduction comprises, first, mixing metal salts in a solvent. Second, a reducing agent is added to the solvent at a temperature in the range of 100&deg; C. to 350&deg; C. Third, the nanoparticles dispersion is stabilized. Fourth, the nanoparticles are precipitated from the nanoparticle dispersion. Finally, the nanoparticles are re-dispersed into the solvent. The metal salt comprises a combination of FeCl , FeCl , Fe(OOCR) , Fe(RCOCHCOR) , CoCl , Co(OOCR) , Co(RCOCHCOR) , and one of Pt(RCOCHCOR) , PtCl . The reducing agent comprises one of MBR H, MH, M naphthalides, and polyalcohol; wherein R comprises one of H and an alkyl group, wherein M comprises one of Li, Na, and K. Long chain alkyl diols, and alkyl alcohol, can be used as a co-surfactant or a co-reducing agent to facilitate nanoparticle growth and separation.

Metal salt reduction to form alloy nanoparticles

A laminar structure upon a substrate is formed from a) a lattice layer comprising DNA (deoxyribonucleic acid) segments arranged to form cells of the lattice layer, and b), at least one nanoparticle being disposed within each cell of the lattice layer. The nanoparticles are preferably of substantially uniform diameter not exceeding 50 nanometers. A coating may be applied to adhere the the particles to the substrate and to maintain their substantially uniform spaced-apart relationship. The DNA lattice layer is fabricated using known automated synthetis methods, and is designed to contain specific nucleotide base sequences which cause the DNA to form an ordered array of openings, or lattice cells, by self-assembly. Self-assembly of the DNA lattice may be at an air-liquid interface, or in solution. A preferred embodiment is a magnetic storage medium in which the particles are magnetic particles with diameters in the range of 5-20 nm., the particles being organized in square information bits with each bit holding of 4, 9, 16, 25 etc. particles to produce areal information storage densities on the order of 1000 gigabits (one terabit) per square inch. The lattice of bits may be stabilized and protected by a deposited thin film, hard, abrasion-resistant coating.

Nanoparticle structures utilizing synthetic DNA lattices

The invention provides a method and related apparatus to link and/or pattern self-assembled first objects to a second object. Each of the first object (e.g., a nanoparticle) can be embedded in a mobile binder (i.e., a stabilizer). The invention applies energy to the first object and stabilizer, links this first object to the second object, and provides a controlled linkage of the first object with respect to the second object. Applying this procedure to many such objects results in a larger areal arrangement of these linked objects. An appropriate solvent may be used to remove non-linked objects, yielding a patterned array. Thermal annealing can be applied to control the physical and chemical properties of the array.

A method and structure for forming magnetic alloy nanoparticles includes forming a metal salt solution with a reducing agent and stabilizing ligands, introducing an organometallic compound into the metal salt solution to form a mixture, heating the mixture to a temperature between 260&deg; and 300&deg; C., and adding a flocculent to cause the magnetic alloy nanoparticles to precipitate out of the mixture without permanent agglomeration. The deposition of the alkane dispersion of FePt alloy particles, followed by the annealing results in the formation of a shiny FePt nanocrystalline thin film with coercivity ranging from 500 Oe to 6500 Oe.

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Millwood, NY, United States of America

Shouheng Sun