1. Introduction 20642. Synthesis of Magnetic Nanoparticles 20662.1. Classical Synthesis by Coprecipitation 20662.2. Reactions in Constrained Environments 20682.3. Hydrothermal and High-TemperatureReactions20692.4. Sol-Gel Reactions 20702.5. Polyol Methods 20712.6. Flow Injection Syntheses 20712.7. Electrochemical Methods 20712.8. Aerosol/Vapor Methods 20712.9. Sonolysis 20723. Stabilization of Magnetic Particles 20723.1. Monomeric Stabilizers 20723.1.1. Carboxylates 20733.1.2. Phosphates 20733.2. Inorganic Materials 20733.2.1. Silica 20733.2.2. Gold 20743.3. Polymer Stabilizers 20743.3.1. Dextran 20743.3.2. Polyethylene Glycol (PEG) 20753.3.3. Polyvinyl Alcohol (PVA) 20753.3.4. Alginate 20753.3.5. Chitosan 20753.3.6. Other Polymers 20753.4. Other Strategies for Stabilization 20764. Methods of Vectorization of the Particles 20765. Structural and Physicochemical Characterization 20785.1. Size, Polydispersity, Shape, and SurfaceCharacterization20795.2. Structure of Ferro- or FerrimagneticNanoparticles20805.2.1. Ferro- and Ferrimagnetic Nanoparticles 20805.3. Use of Nanoparticles as Contrast Agents forMRI20825.3.1. High Anisotropy Model 20845.3.2. Small Crystal and Low Anisotropy EnergyLimit20855.3.3. Practical Interests of Magnetic NuclearRelaxation for the Characterization ofSuperparamagnetic Colloid20855.3.4. Relaxation of Agglomerated Systems 20856. Applications 20866.1. MRI: Cellular Labeling, Molecular Imaging(Inﬂammation, Apoptose, etc.)20866.2.

Magnetic Iron Oxide Nanoparticles: Synthesis, Stabilization, Vectorization, Physicochemical Characterizations, and Biological Applications

This review summarizes recent developments in the theory of spin glasses, as well as pertinent experimental data. The most characteristic properties of spin glass systems are described, and related phenomena in other glassy systems (dielectric and orientational glasses) are mentioned. The Edwards-Anderson model of spin glasses and its treatment within the replica method and mean-field theory are outlined, and concepts such as "frustration," "broken replica symmetry," "broken ergodicity," etc., are discussed. The dynamic approach to describing the spin glass transition is emphasized. Monte Carlo simulations of spin glasses and the insight gained by them are described. Other topics discussed include site-disorder models, phenomenological theories for the frozen phase and its excitations, phase diagrams in which spin glass order and ferromagnetism or antiferromagnetism compete, the Ne\'el model of superparamagnetism and related approaches, and possible connections between spin glasses and other topics in the theory of disordered condensed-matter systems.

Spin glasses: Experimental facts, theoretical concepts, and open questions

Mechanical alloying (MA) is a solid-state powder processng technique involving repeated welding, fracturing, and rewelding of powder particles in a high-energy ball mill. Originally developed to produce oxide-dispersion strengthened (ODS) nickel- and iron-base superalloys for applications in the aerospace industry, MA has now been shown to be capable of synthesizing a variety of equilibrium and non-equilibrium alloy phases starting from blended elemental or prealloyed powders. The non-equilibrium phases synthesized include supersaturated solid solutions, metastable crystalline and quasicrystalline phases, nanostructures, and amorphous alloys. Recent advances in these areas and also on disordering of ordered intermetallics and mechanochemical synthesis of materials have been critically reviewed after discussing the process and process variables involved in MA. The often vexing problem of powder contamination has been analyzed and methods have been suggested to avoid/minimize it. The present understanding of the modeling of the MA process has also been discussed. The present and potential applications of MA are described. Wherever possible, comparisons have been made on the product phases obtained by MA with those of rapid solidification processing, another non-equilibrium processing technique.

Mechanical Alloying And Milling

In the coming decade, the ability to sense and detect the state of biological systems and living organisms optically, electrically and magnetically will be radically transformed by developments in materials physics and chemistry. The emerging ability to control the patterns of matter on the nanometer length scale can be expected to lead to entirely new types of biological sensors. These new systems will be capable of sensing at the single-molecule level in living cells, and capable of parallel integration for detection of multiple signals, enabling a diversity of simultaneous experiments, as well as better crosschecks and controls.

/pdf/the-use-of-nanocrystals-in-biological-detection-3f8dgrg9fx.pdf

The use of nanocrystals in biological detection

http://files.janapv.webnode.cz/200000097-8a03f8afdf/ex_bias_nano.pdf

Exchange bias in nanostructures

Magnetic Relaxation in Fine‐Particle Systems

On the models for interparticle interactions in nanoparticle assemblies: comparison with experimental results

Thermal variation of the relaxation time of the magnetic moment of gamma -Fe2O3 nanoparticles with interparticle interactions of various strengths.

From pure superparamagnetic regime to glass collective state of magnetic moments in γ-Fe2O3 nanoparticle assemblies

A study of magnetic properties in the insulating spinel ${\mathrm{ZnCr}}_{1.6}$${\mathrm{Ga}}_{0.4}$${\mathrm{O}}_{4}$ (chromium ions in octahedral sites) has been made by carrying out low-field dc- and ac-susceptibility measurements as well as neutron diffraction, M\"ossbauer, and EPR experiments, which all give evidence of spin-glass-like behavior. The topological frustration, connected with the high ground-state degeneracy of the antiferromagnetic spinel octahedral sublattice, is the origin of the spin-glass ordering. Strong nearest-neighbor antiferromagnetic interactions are dominant in the system, leading to short-range magnetic order which appears at temperatures much higher than the freezing temperature defined by the acsusceptibility cusp [$T(\ensuremath{\nu}=17 \mathrm{Hz})=2.50$ K is frequency dependent]. The thermoremanent magnetization does not vanish at ${T}_{f}$, suggesting the existence of uncompensated clusters blocked above ${T}_{f}$. A paramagnetic behavior is observed below $T=1$ K, providing evidence for the presence of unfrozen spins below ${T}_{f}$ (entropic clusters).

J.L. Dormann

Papers

Magnetic Relaxation in Fine‐Particle Systems

On the models for interparticle interactions in nanoparticle assemblies: comparison with experimental results

Thermal variation of the relaxation time of the magnetic moment of gamma -Fe2O3 nanoparticles with interparticle interactions of various strengths.

From pure superparamagnetic regime to glass collective state of magnetic moments in γ-Fe2O3 nanoparticle assemblies

Spin-glass behavior in an antiferromagnetic frustrated spinel: ZnCr 1.6 Ga 0.4 O 4