INTRINSIC FINE-SCALE STRUCTURE IN COMPLEX MATERIALS: BEYOND GLOBAL CRYSTALLOGRAPHIC ANALYSIS

MIGLIORI, A. ; AL, ET

Los Alamos National Laboratory

关键词: Fine Structure;    Crystallography;    Crystal Structure;    36 Materials Science;    Elasticity;   

DOI  :  10.2172/768850
RP-ID  :  LA-UR-00-5756
RP-ID  :  W-7405-ENG-36
RP-ID  :  768850

美国|英语

来源: UNT Digital Library

【 摘 要 】

Many important classes of materials owe their interesting properties to structures and patterns produced by local atomic deviations from ideal crystallographic positions. The pattern scale may vary from a few atomic spacings to many microns. In a macroscopic sample these deviations may still average to an ideal lattice while retaining the intrinsic fine-scale structures, or a phase transition may create a pattern of variants of a new crystallographic structure. We have carried out experiments on the formation of fine-scale structures in a range of materials, particularly those produced by phase transitions. We have used Resonant Ultrasound Spectroscopy for elastic properties and dissipation, neutron pair-distribution function, and electronic transport measurements to characterize samples. We have carried out extensive dynamical modeling based on Ginzberg-Landau formalisms to simulate the development and appearance of the structures. Our results highlight the importance of long-range strain fields and the intrinsic unstable equilibrium features of the materials studied.