Über die Autorin bzw. den Autor

ROBERT LECKIE is the author of over thirty books on military history, including George Washington's War: The Saga of the American Revolution, None Died in Vain: The Saga of the Civil War, and most recently, Okinawa: The Last Battle of World War II.

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"Leckie is a gifted writer with the ability to explain complicated military matters in layperson s terms, while sustaining the drama involved in a life-and-death struggle. His portraits of the key players in that struggle . . . are seamlessly interwoven with his exciting narrative." Booklist"As always, [Leckie] describes the maneuvers, battles, and results in telling detail with a cinematic style, and his portraits . . . are first-rate." The Dallas Morning News"Leckie s accounts of battles, important individuals, and the role of Native Americans bring to life the distant drama of the French and Indian Wars." The Daily Reflector

With his celebrated sense of drama and eye for colorful detail, acclaimed military historian Robert Leckie charts the long, savage conflict between England and France in their quest for supremacy in pre-Revolutionary America. Packed with sharply etched profiles of all the major players including George Washington, Samuel de Champlain, William Pitt, Edward Braddock, Count Frontenac, James Wolfe, Thomas Gage, and the nobly vanquished Marquis de Montcalm this panoramic history chronicles the four great colonial wars: the War of the Grand Alliance (King William s War), the War of the Spanish Succession (Queen Anne s War), the War of the Austrian Succession (King George s War), and the decisive French and Indian War (the Seven Years War). Leckie not only provides perspective on exactly how the New World came to be such a fiercely contested prize in Western Civilization, but also shows us exactly why we speak English today instead of French and reminds us how easily things might have gone the other way.

Aus dem Klappentext

"Leckie is a gifted writer with the ability to explain complicated military matters in layperson’s terms, while sustaining the drama involved in a life-and-death struggle. His portraits of the key players in that struggle . . . are seamlessly interwoven with his exciting narrative." –Booklist"As always, [Leckie] describes the maneuvers, battles, and results in telling detail with a cinematic style, and his portraits . . . are first-rate."–The Dallas Morning News"Leckie’s accounts of battles, important individuals, and the role of Native Americans bring to life the distant drama of the French and Indian Wars."–The Daily Reflector

With his celebrated sense of drama and eye for colorful detail, acclaimed military historian Robert Leckie charts the long, savage conflict between England and France in their quest for supremacy in pre-Revolutionary America. Packed with sharply etched profiles of all the major players–including George Washington, Samuel de Champlain, William Pitt, Edward Braddock, Count Frontenac, James Wolfe, Thomas Gage, and the nobly vanquished Marquis de Montcalm–this panoramic history chronicles the four great colonial wars: the War of the Grand Alliance (King William’s War), the War of the Spanish Succession (Queen Anne’s War), the War of the Austrian Succession (King George’s War), and the decisive French and Indian War (the Seven Years’ War). Leckie not only provides perspective on exactly how the New World came to be such a fiercely contested prize in Western Civilization, but also shows us exactly why we speak English today instead of French–and reminds us how easily things might have gone the other way.

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"A Few Acres of Snow"

John Wiley & Sons

Chapter One

1.1 Some Words about Nanoparticles

First of all, it is necessary to consider the general concepts related to the nanosized objects. A nanoobject is a physical object differing appreciably in properties from the corresponding bulk material and having at least 1 nm dimension (not more than 100 nm). When dealing with nanoparticles, magnetic properties (and other physical ones) are size dependent to a large extent. Therefore, particles whose sizes are comparable with (or lesser than) the sizes of magnetic domains in the corresponding bulk materials are the most interesting from a magnetism scientist viewpoint.

Nanotechnology is the technology dealing with both single nanoobjects and materials, and devices based on them, and with processes that take place in the nanometer range. Nanomaterials are those materials whose key physical characteristics are dictated by the nanoobjects they contain. Nanomaterials are classified into compact materials and nanodispersions. The first type includes so-called nanostructured materials, i.e., materials isotropic in the macroscopic composition and consisting of contacting nanometer-sized units as repeating structural elements. Unlike nanostructured materials, nanodispersions include a homogeneous dispersion medium (vacuum, gas, liquid, or solid) and nanosized inclusions dispersed in this medium and isolated from each other. The distance between the nanoobjects in these dispersions can vary over broad limits from tens of nanometers to fractions of a nanometer. In the latter case, we are dealing with nanopowders whose grains are separated by thin (often monoatomic) layers of light atoms, which prevent them from agglomeration. Materials containing magnetic nanoparticles, isolated in nonmagnetic matrices at the distances longer than their diameters, are most interesting for magnetic investigations.

A nanoparticle is a quasi-zero-dimensional (0D) nanoobject in which all characteristic linear dimensions are of the same order of magnitude (not more than 100 nm). Nanoparticles can basically differ in their properties from larger particles, for example, from long- and well-known ultradispersed powders with a grain size above 0.5 m. As a rule, nanoparticles are shaped like spheroids. Nanoparticles with a clearly ordered arrangement of atoms (or ions) are called nanocrystallites. Nanoparticles with a clear-cut discrete electronic energy levels are often referred to as "quantum dots" or "artificial atoms"; most often, they have compositions of typical semiconductor materials, but not always. Many magnetic nanoparticles have the same set of electronic levels.

Nanoparticles are of great scientific interest because they represent a bridge between bulk materials and molecules and structures at an atomic level. The term "cluster," which has been widely used in the chemical literature in previous years, is currently used to designate small nanoparticles with sizes less than 1 nm. Magnetic polynuclear coordination compounds (magnetic molecular clusters) belong to the special type of magnetic materials often with unique magnetic characteristics. Unlike nanoparticles, which always have the distributions in sizes, molecular magnetic clusters are the fully identical small magnetic nanoparticles. Their magnetism is usually described in terms of exchange-modified paramagnetism.

Nanorods and nanowires, as shown in Figure 1.1, are quasi-one-dimensional (ID) nanoobjects. In these systems, one dimension exceeds by an order of magnitude the other two dimensions, which are in the nanorange.

The group of two-dimensional objects (2D) includes planar structures - nanodisks, thin-film magnetic structures, magnetic nanoparticle layers, etc., in which two dimensions are an order of magnitude greater than the third one, which is in the nanometer range. The nanoparticles are considered by many authors as giant pseudomolecules having a core and a shell and often also external functional groups. The unique magnetic properties are usually inherent in the particles with a core size of 2-30 nm. For magnetic nanoparticles, this value coincides (or less) with the size of a magnetic domain in most bulk magnetic materials. Methods of synthesis and properties of nanoparticles were considered in the books and reports.

1.2 Scope

Among many of known nanomaterials, the special position belong to those, in which isolated magnetic nanoparticles (magnetic molecular clusters) are divided by dielectric nonmagnetic medium. These nanoparticles present giant magnetic pseudoatoms with the huge overall magnetic moment and "collective spin." In this regard nanoparticles fundamentally differ from the classic magnetic materials with their domain structure. As a result of recent investigations, the new physics of magnetic phenomena - nanomagnetism - was developed. Nanomagnetism advances include superparamagnetism, ultrahigh magnetic anisotropy and coercive force, and giant magnetic resistance. The fundamental achievement of the last time became the development of the solution preparation of the objects with advanced magnetic parameters.

Currently, unique physical properties of nanoparticles are under intensive research. A special place belongs to the magnetic properties in which the difference between a massive (bulk) material and a nanomaterial is especially pronounced. In particular, it was shown that magnetization (per atom) and the magnetic anisotropy of nanoparticles could be much greater than those of a bulk specimen, while differences in the Curie or Nel temperatures between nanoparticle and the corresponding microscopic phases reach hundreds of degrees. The magnetic properties of nanoparticles are determined by many factors, the key of these including the chemical composition, the type and the degree of defectiveness of the crystal lattice, the particle size and shape, the morphology (for structurally inhomogeneous particles), the interaction of the particle with the surrounding matrix and the neighboring particles. By changing the nanoparticle size, shape, composition, and structure, one can control to an extent the magnetic characteristics of the material based on them. However, these factors cannot always be controlled during the synthesis of nanoparticles nearly equal in size and chemical composition; therefore, the properties of nanomaterials of the same type can be markedly different.

In addition, magnetic nanomaterials were found to possess a number of unusual properties - giant magnetoresistance, abnormally high magnetocaloric effect, and so on.

Nanomagnetism usually considers so-called single-domain particles; typical values for the single-domain size range from 15 to 150 nm. However, recently the researchers focused their attention on the particles, whose sizes are smaller than the domain size range; a single particle of size comparable to the minimum domain size would not break up into domains; there is a reason to call these particles domain free magnetic nanoparticles (DFMN). Each such particle behaves like a giant paramagnetic atom and shows superparamagnetic behavior when the temperature is above the so-called blocking temperature. The experiment shows that the last one can vary in wide diapasons, from few kelvins till higher than room temperature.

Thus, this is a book describing what we need to know to perform nanoscale magnetism - the...