X-ray magnetic circular dichroism in d and f ferromagnetic materials: recent theoretical progress. Part I

• Опубліковано в: : Физика низких температур
• Дата: 2008
• Автори: Antonov, V.N., Shpak, A.P., Yaresko, A.N.
• Формат: Стаття
• Мова: Англійська
• Опубліковано: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2008
• Теми: Обзоp
• Онлайн доступ: https://nasplib.isofts.kiev.ua/handle/123456789/116810
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: X-ray magnetic circular dichroism in d and f ferromagnetic materials: recent theoretical progress. Part I / V.N. Antonov, A.P. Shpak, A.N. Yaresko // Физика низких температур. — 2008. — Т. 34, № 2. — С. 107–147. — Бібліогр.: 198 назв. — англ.

The curreThe current status of theoretical understanding of the x-ray magnetic circular dichroism (XMCD) of 4 f
 and 5 f compounds is reviewed. Energy band theory based upon the local spin-density approximation
 (LSDA) describes the XMCD spectra of transition metal compounds with high accuracy. However, the
 LSDA does not suffice for lanthanide compounds which have a correlated 4 f shell. A satisfactory description
 of the XMCD spectra could be obtained by using a generalization of the LSDA, in which explicitly f
 electron Coulomb correlation are taken into account (LSDA + U approach). As examples of this group we
 consider GdN compound. We also consider uranium 5 f compounds. In those compounds where the 5 f electrons
 are rather delocalized, the LSDA describes the XMCD spectra reasonably well. As example of this
 group we consider UFe₂. Particular differences occur for the uranium compounds where the 5 f electrons are
 neither delocalized nor localized, but more or less semilocalized. Typical examples are UXAl (X = Co, Rh,
 and Pt), and UX (X = S, Se, Te). The semilocalized 5 f ’s are, however, not inert, but their interaction with
 conduction electrons plays an important role. We also consider the electronic structure and XMCD spectra
 of heavy-fermion compounds UPt₃, URu₂Si₂, UPd₂Al3₃, UNi₂Al₃, and UBe₁₃ where the degree of the 5 f localization
 is increased in comparison with other uranium compounds. The electronic structure and XMCD
 spectra of UGe₂ which possesses simultaneously ferromagnetism and superconductivity also presented. Recently
 achieved improvements for describing 5 f compounds are discussed.