Defects and hyperfine interactions in binary Fe-Al alloys studied by positron annihilation and Mssbauer spectroscopies  

作　　者：邓文 孙小香 谭少希 李玉霞 熊定康 黄宇阳 

机构地区：[1]College of Physical Science and Engineering, Guangxi University

出　　处：《Chinese Physics C》2013年第12期125-129,共5页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China(10764001,51061002);Program for Science and Technology Innovation Team of Guangxi University

摘　　要：The defects, the behavior of 3d electrons and the hyperfine interactions in binary Fe-Al alloys with different Al contents have been studied by measurements of positron lifetime spectra, coincidence Doppler broadening spectra of positron annihilation radiation and M？ssbauer spectra. The results show that on increasing the Al content in Fe-Al alloys, the mean positron lifetime of the alloys increase, while the mean electron density of the alloys decrease. The increase of Al content in binary Fe-Al alloys will decrease the amount of unpaired 3d electrons; as a consequence the probability of positron annihilation with 3d electrons and the hyperfine field decrease rapidly. M？ssbauer spectra of binary Fe-Al alloys with Al content less than 25 at.% show discrete sextets and these alloys make a ferromagnetic contribution at room temperature. The M？ssbauer spectrum of Fe70Al30 shows a broad singlet. As Al content higher than 40 at.%, the M？ssbauer spectra of these alloys are singlet, that is, the alloys are paramagnetic. The behavior of a 3d electron and its effect on the hyperfine field of the binary Fe-Al alloy has been discussed.The defects, the behavior of 3d electrons and the hyperfine interactions in binary Fe-Al alloys with different Al contents have been studied by measurements of positron lifetime spectra, coincidence Doppler broadening spectra of positron annihilation radiation and M？ssbauer spectra. The results show that on increasing the Al content in Fe-Al alloys, the mean positron lifetime of the alloys increase, while the mean electron density of the alloys decrease. The increase of Al content in binary Fe-Al alloys will decrease the amount of unpaired 3d electrons; as a consequence the probability of positron annihilation with 3d electrons and the hyperfine field decrease rapidly. M？ssbauer spectra of binary Fe-Al alloys with Al content less than 25 at.% show discrete sextets and these alloys make a ferromagnetic contribution at room temperature. The M？ssbauer spectrum of Fe70Al30 shows a broad singlet. As Al content higher than 40 at.%, the M？ssbauer spectra of these alloys are singlet, that is, the alloys are paramagnetic. The behavior of a 3d electron and its effect on the hyperfine field of the binary Fe-Al alloy has been discussed.

关 键 词：Hyperfine interactions 3d electrons positron annihilation MSssbauer spectroscopy 

分 类 号：TG131[一般工业技术—材料科学与工程]