We have characterized the structural and magnetic properties of low-temperature molecular-beam epitaxy grown Ge: Mn by means of high-resolution transmission electron microscopy ͑HR-TEM͒, energy dispersive x-ray spectroscopy, and superconducting quantum interference device ͑SQUID͒ magnetometry. We find a coherent incorporation of Mn 5 Ge 3 clusters in an epitaxially grown Ge: Mn matrix, which shows the characteristics of a diluted magnetic semiconductor phase of Mn-doped Ge. The clusters are preferentially oriented with the hexagonal ͓0001͔ direction parallel to the ͓001͔ growth direction of the Ge: Mn matrix, as determined from both HR-TEM and SQUID measurements.

The presence of FeCl2 catalyst enabled the growth of onedimensional nanostructures directly during the pyrolysis of highly porous monoliths, produced from a polysiloxane preceramic polymer with the aid of a gas-generating porogen. Either silicon nitride or silicon carbide nanowires were formed, with a length of several micrometers, depending on the processing atmosphere. Increasing the pyrolysis temperature caused an increase in the length and the amount of nanostructures produced. The remaining matrix consisted of an incompletely crystallized Si–O–C phase, containing SiC crystals and either graphitic (N2 pyrolysis) or amorphous carbon (Ar pyrolysis). X-ray diffraction data and high-resolution transmission electron microscopy investigations combined with electron energy loss and energydispersive X-ray spectroscopy methods enabled to ascertain the growth mechanisms for the nanowires, which depended on the pyrolysis atmosphere (gas phase reaction for N2 pyrolysis; vapor–liquid–solid for Ar pyrolysis)

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The relationship between magnetism and morphology of pseudomorphic ultrathin films of fcc Fe on Cu(001) is reexamined in view of morphological data obtained with scanning tunneling microscopy. Two types of 6lms showing difFerent magnetic properties were investigated. Films prepared at 300 K are found to grow in a good layer-by-layer mode. Their magnetism appears to be inBuenced by structural instabilities connected with a martensitic fcc~bcc transformation. Films deposited at 130 K and later annealed at 300 K grow in a Stranski-Krastanov-like mode, resulting in a drastically diferent surface morphology. They are found to be structurally stable in the region where the spin reorientation takes place. An attempt is made to correlate the enhanced roughness of these films with their magnetic properties. Finally, the connection between the morphological percolation and the onset of long-range ferromagnetic ordering is discussed. The percolation of the 6rst layer is found to be insufBcient to establish long-range ferromagnetic ordering in these 6lms.

Phenomena of metal dusting on iron and nickel (and their alloys) were studied by characterizing both microstructure and nanochemistry of the reaction zones using TEM and AEM techniques. While in case of iron a metastable carbide (cementite) is formed nickel directly disintegrates. In the chromium‐rich steel HK40 and the chromium‐rich Ni‐base alloy Inconel 600 some microstructural chromium dependent features were observed with protective effects against metal dusting. Independent of these differences, in all groups of materials a fundamental common starting mechanism on the atomic scale could be deduced, which first of all comprises the arrangement of basal graphite lattice planes perpendicularly oriented to the carbide (or metal) surface acting as active sites in the disintegration process.