The electronic structures of EuNi2Ge2 and GdNi2Ge2 have been investigated using photoemission spectroscopy. The majority of the photoemission intensity near E[subscript F] was due to the mostly Ni 3d states in both materials. CIS spectra were recorded at selected initial-state binding energies (BEs) across the excitation energy range of the Ni 3p threshold in EuNi2Ge2. It is apparent that there is strong Ni d character throughout the valence band from CIS spectra. Resonance measurements of the Eu 4d[Reaction goes right]4f excitations in EuNi2Ge2 reveal that Eu 4f states are localized around 2 eV below E[subscript F]. It is observed that Gd 4f peak in GdNi2Ge2 is more tightly bound by 6.4 eV than in Eu 4f peak in EuNi2Ge2. We have seen a resonant enhancement of the Ni 3d satellite at about 7.4 eV BE, indicating Ni 3d character around the Fermi edge in EuNi2Ge2. The Ni 3d partial spectral weights (PSW) from the Ni 3p[Reaction goes right]3d RPES measurements show that they are very close to the calculated Ni 3d density of states for both materials. We have measured Constant-Final-State (CFS) and Constant-Initial-State (CIS) spectra in an attempt to check the valence of the Eu ion in EuNi2Ge2, and it is verified as 2+. The measured CFS spectra of GdNi2Ge2 was almost the same as those of EuNi2Ge2 and Gd metal, indicating that Gd ions in GdNi2Ge2 are trivalent with the same 4f7 configuration as the Eu ion in EuNi2Ge2. We present experimental energy bands mapped from normal-emission photoelectron spectra of EuNi2Ge2 and GdNi2Ge2 (001) surfaces using synchrotron radiation with increasing photon energies from 14 eV to 54 eV (to 44 eV in the case of GdNi2Ge2). Four and three major photoemission features disperse along the normal [001] Brillouin zone (BZ) direction direction in EuNi2Ge2 and GdNi2Ge2, respectively, in good agreement with the band calculations. We studied quantitatively the effects of band filling on the electronic structures by observing a rigid-band shift of E[subscript F] corresponding simply to an increase of one conduction electron upon going from EuNi2Ge2 to GdNi2Ge2. Segments of the Fermi surfaces (FSs) were mapped by ARPES in the [Gamma]XPZ plane of the Brillouin zones (BZs) for both EuNi2Ge2 and GdNi2Ge2, which are in good agreement with band calculations. We studied how the FS is changed in the [Gamma]XPZ planes of the BZ when one electron is added to EuNi2Ge2, corresponding to GdNi2Ge2, based on the rigid-band approximation. In conclusion, these compounds which give the same Hund's rule ground state (8S--[subscript /]2) were one of suitable systems for the study of effects of band filling on electric structures based on a rigid-band model as a first-order approximation.

EuNi2Ge2 and GdNi2Ge2 are two members of the RT2X2 (R = rare earth, T = transition metal and X = Si, Ge) family of intermetallic compounds, which has been studied since the early 1980s. These ternary rare-earth intermetallic compounds with the tetragonal ThCr2Si2 structure are known for their wide variety of magnetic properties, Extensive studies of the RT2X2 series can be found in Refs [ 1,2,3]. The magnetic properties of the rare-earth nickel germanides RNi2Ge2 were recently studied in more detail [4]. The purpose of this dissertation is to investigate the electronic structure (both valence band and shallow core levels) of single crystals of EuNi2Ge2 and GdNi2Ge2 and to check the assumptions that the f electrons are non-interacting and, consequently, the rigid-band model for these crystals would work [11], using synchrotron radiation because, to the best of our knowledge, no photoemission measurements on those have been reported. Photoemission spectroscopy has been widely used to study the detailed electronic structure of metals and alloys, and especially angle-resolved photoemission spectroscopy (ARPES) has proven to be a powerful technique for investigating Fermi surfaces (FSs) of single-crystal compounds.

This volume of the Handbook illustrates the rich variety of topics covered by rare earth science. Three chapters are devoted to the description of solid state compounds: skutterudites (Chapter 211), rare earth -antimony systems (Chapter 212), and rare earth-manganese perovskites (Chapter 214). Two other reviews deal with solid state properties: one contribution includes information on existing thermodynamic data of lanthanide trihalides (Chapter 213) while the other one describes optical properties of rare earth compounds under pressure (Chapter 217). Finally, two chapters focus on solution chemistry. The state of the art in unraveling solution structure of lanthanide-containing coordination compounds by paramagnetic nuclear magnetic resonance is outlined in Chapter 215. The potential of time-resolved, laser-induced emission spectroscopy for the analysis of lanthanide and actinide solutions is presented and critically discussed in Chapter 216.

Rare Earth Intermetallics provides an account of the magnetic characteristics of rare earth intermetallics. This book discusses bulk magnetic characteristics, such as temperature dependence of susceptibility, saturation magnetization, nature of the cooperative magnetic phase, low temperature specific heats, and related thermal properties. Other topics include the magnetic interactions, crystal field interaction by the operator equivalent method, and rare earth-nontransition metal systems. The miscellaneous IVA compounds, rare earth substitution, variation in the iron moment, and compounds with 4d and 5d transition metals are also elaborated in this text. This publication is recommended for students and researchers interested in rare earth intermetallics.

Handbook on the Physics and Chemistry of Rare Earths: Including Actinides, Volume 59, presents the latest release in this continuous series that covers all aspects of rare earth science, including chemistry, life sciences, materials science and physics. Presents up-to-date overviews and new developments in the field of rare earths, covering both their physics and chemistry Contains individual chapters that are comprehensive and broad, along with critical reviews Provides contributions from highly experienced, invited experts