论文标题
中子辐射引起的磁化和石墨高温下的持续缺陷
Neutron-Irradiation Induced Magnetization and Persistent Defects at High Temperatures in Graphite
论文作者
论文摘要
在Trombay的CIRUS研究反应堆中，已在50年的中子辐照的石墨样品上进行了结构和磁化研究。中子衍射研究表明，受辐照的石墨样品中的缺陷不能很好地退火，直到高温大于653 k的高温下，wigner wigner势得多。我们推断，与层间缺陷相比，残留的缺陷可能是内在的弗伦克尔缺陷，与存储Wigner能量的层间缺陷不同，它们不会存储大能量。对辐照石墨的磁化研究即使在300 K时也显示出铁磁行为，并且基于自旋极化密度功能功能理论的5 K-Initio计算在5 K. Ab-Initio计算时也表明，缺陷石墨中的磁性基本限于单个2式碳纤维的碳ATOM，而单个2条配方的碳atom均位于远处均位于Hexomotal in hexomotal ins exomotal ins exomotal ins exomotal insexomal inseaxomal insexomal insexomal层。
Structural as well as magnetization studies have been carried out on graphite samples irradiated by neutrons over 50 years in the CIRUS research reactor at Trombay. Neutron diffraction studies reveal that the defects in irradiated graphite samples are not well annealed and remain significant up to high temperatures much greater than 653 K where the Wigner energy is completely released. We infer that the remnant defects may be intralayer Frenkel defects, which do not store large energy, unlike the interlayer Frenkel defects that store the Wigner energy. Magnetization studies on the irradiated graphite show ferromagnetic behavior even at 300 K and a large additional paramagnetic contribution at 5 K. Ab-initio calculations based on the spin-polarized density-functional theory show that the magnetism in defected graphite is essentially confined on to a single 2-coordinated carbon atom that is located around a vacancy in the hexagonal layer.
