NMR study of the ternary carbides M2AlC(M=Ti, V, Cr)

• Main Authors: Jing-Ying Lin, 林景穎
• Other Authors: Chin-Shan Lue
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/65142678881587892956

碩士 === 國立成功大學 === 物理學系碩博士班 === 94 === Abstract Transit-metal carbides M2AlC (M= Ti, V, Cr) have many technological applications for their high elastic modulus, damage tolerance, excellent thermal and electrical conductivity. In this letter we investigated the electronic structure and properties of the series ternary carbides M2AlC by nuclear magnetic resonance (NMR) techniques. In 27Al NMR spectrum of these materials, anisotropic Knight shift and quadrupole effects have been identified. The isotropic Knight shift varies from positive for Ti2AlC and V2AlC to negative for Cr2AlC, corresponding to the transfer hyperfine field of the Al-M bond increasing with the d electron count. The quadrupole frequency points to the important Al-M bonding nature. T1 measurements provide the Al-s Fermi level DOS for Ti2AlC and V2AlC correlate with the transition d electron count. In addition, the temperature dependent T1 between 300K and 77K indicated the paramagnetic feature in Cr2AlC.