Abstract
We have studied temperature evolution of the local as well as the average crystal structure of MgB 2 and Mg 0.5Al 0.5B 2 using real-space atomic pair distribution function (PDF) measured by high resolution neutron powder diffraction in a wide temperature range of T=10-600 K. The mean square relative displacements (MSRD) of atomic B-B, B-Mg (B-Al) pairs are compared with mean-square displacements (MSD) to calculate atomic correlations. In spite of the enhanced atomic disorder in Mg 0.5Al 0.5B 2, where the boron-boron, and boron-magnesium pair motions are found to be small, we find that the same atomic correlations in MgB 2 assume even slightly lower values and remain nearly constant in a wide temperature range of 0-600 K. This anomalous behavior and its physical interpretation provoke new questions on our understanding to the local lattice dynamics in this material.
Original language | English |
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Pages (from-to) | 505-510 |
Number of pages | 6 |
Journal | Journal of Superconductivity and Novel Magnetism |
Volume | 20 |
Issue number | 7-8 |
DOIs | |
State | Published - Nov 2007 |
Externally published | Yes |
Keywords
- MgB
- Neutron diffraction