Mossbauer Spectroscopy Studies of Amorphous Metallic Solids
- PDF / 1,204,333 Bytes
- 14 Pages / 415.8 x 635.4 pts Page_size
- 99 Downloads / 249 Views
157
MOSSBAUER SPECTROSCOPY STUDIES OF AMORPHOUS METALLIC SOLIDS*
C. L. CHIEN The Johns Hopkins University, Baltimore,
Maryland
21218
ABSTRACT M8ssbauer spectroscopy as applied to the studies of amorphous metallic, and often magnetic solids will be discussed. The advantages of using this microscopic technique will be compared with others in terms of obtaining information on electronic, magnetic, hyperfine, structural and other properties. Examples of magnetic ordering structures, concentration dependence of ordering temperature, hyperfine field distribution, spin-wave excitations, crystallization behavior, quadrupole interaction, isomer shift, etc., as obtained by M8ssbauer spectroscopy will be presented.
INTRODUCTION In the 1960's, Duwez and his co-workers demonstrated that amorphous metals can be made by extremely rapid cooling from the melt (cooling rates in excess of 105 K/sec) [1]. Since then several other methods have successfully been used to fabricate amorphous metallic solids. In recent years the field of amorphous metallic solids or metallic glasses has been one of the most active areas of research in condensed matter physics. The term amorphous metallic solid and metallic glass are here taken to be synonymous although some authors reserve the term glass to mean materials formed exclusively from the melt. Metallic is used in the general sense to indicate materials having high concentrations of metallic elements, even though for example, few have electrical conductivities that approach that of a good metal. Given sufficient activation energy (e.g. heat), the metallic glasses invariably and irreversibly transform into crystalline phases, since the amorphous state is metastable. Research in the field of amorphous metals has revealed many unusual mechanical, electrical and magnetic properties. Both because of the ease with which transition metals and rare earths can be incorporated into the metallic glasses and because of possible applications, amorphous magnetism has perhaps received the greatest attention. Magnetic bubble memory, magnetic shielding and transformer core are just few examples of such applications [2,3]. Many other practical uses will undoubtedly be found for utilizing the superior properties and inexpensive production of the metallic glasses. Since the first systemetic M8ssbauer studies of metallic glasses by the Caltech group twelve years ago [4], this technique has been widely used in investigations of various amorphous systems. In this paper, we will briefly describe the applications of Mfssbauer spectroscopy and summarize some of the results in the literature. Since metallic glasses will be featured, the results on insulating glasses will not be included [5,6]. In keeping with the emphasis of this Symposium, general features rather than fine details will be presented.
158 FABRICATION AND CHARACTERIZATION OF AMORPHOUS METALLIC SOLIDS
There are generally three ways of making amorphous metallic solids: liquid-quench (piston and anvil, melt spinning) [1,7], vapor deposition (evaporati
Data Loading...
