The structure of a metallic glass system using EXELFS and EXAFS as complementary probes

Abstract

The short-range atomic order around all three constituent atoms in a prototypical bulk metallic glass (BMG) system was probed in a complementary way, using extended X-ray absorption fine structure for neighborhood of the higher atomic number elements, and extended energy loss fine structure (EXELFS) for the lower atomic number ones. The Pd x Ni (80− x) P (20) system is a prototype for a whole class of BMG formers which are 80% transition metal and 20% metalloid. We find that the structure of these BMGs could be explained in terms of those of glasses at the end of the BMG range, namely, Pd 60Ni 20P 20 and Pd 30Ni 50P 20. The binary phosphide crystals near x=0 and 80 are found to be simulate very well the local atomic structure of Pd 30Ni 50P 20 and Pd 60Ni 20P 20 glasses, respectively. The best glass former in this series, Pd 40Ni 40P 20, is best described by a weighted average of Pd 30Ni 50P 20 and Pd 60Ni 20P 20 structures.