P. Monachesi's research while affiliated with Università degli Studi dell'Aquila and other places

Publications (9)

Article
We perform a tight-binding fit of the self-consistent LMTO-LDA electronic structure of CeAg. This allows us to calculate the width DELTA(epsilon) of the Ce 4f-levels due to hybridisation with conduction states. The f-levels are shown to hybridise with p-and d-band states at the Fermi energy.
Article
Self-consistent linear muffin-tin orbital calculations are performed for CeAg. The electronic structure is calculated in the paramagnetic and ferromagnetic phase, for both the cubic and tetragonal symmetry. The presence of hybridization relevant to the Anderson lattice behavior, invoked to interpret the low-temperature properties of this compound,...
Article
We perform self-consistent linear muffin-tin-orbital local-density-approximation (LMTO-LDA) electronic structure calculations for paramagnetic CeAg in the cubic phase to study the hybridization of the Ce f states which is found particularly effective with the Ce d and Ag p states. We also make self-consistent calculations of the electronic structur...
Article
We report the first theoretical results on the magnetization behaviour of CeAg under pressure. According to our self-consistent electronic calculations the magnetic moment, of essentially Ce 4ƒ and 5d origin, decreases by about 50% at the highest pressure of 6 GPa. From the analysis of the electronic structure at several lattice constants we are ab...
Article
An attempt to find a quantitative relationship between magnetic transition temperature and conduction states properties in metallic materials is presented. The exchange interaction among magnetic moments is assumed to be of the Anderson's s-f type and the conduction states have s-d orbital character. The results are analyzed vs. different amount of...
Article
We investigate the indirect exchange interaction between localized moments via conduction bands. The origin of the exchange is assumed to be the Anderson s-f mixing mechanism appropriate to anomalous rare earth and light actinide systems. The conduction states originate from s-orbitals in a CsCl structure. Hubbard correlation in Hartree-Fock approx...
Article
We study the effect of the conduction-electron density of states on magnetic transition temperatures in metallic systems with localized magnetic moments. We assume the indirect-exchange interaction to originate from s-f mixing of the Anderson type and we perform calculations of the coupling parameters, up to fourth-nearest neighbors, in the formali...
Article
We study the influence of interorbital hybridization gammak on the indirect exchange interaction J(k) in a model of two bcc bands of s-type. We report two cases where the stable magnetic structure changes due to gammak. However, gammak generally leaves unchanged the structure, while reducing greatly its stability vs. temperature.
Article
The inclusion of anisotropic terms of tetragonal symmetry in the exchange interaction of polyatomic cubic crystals is investigated. This explains the two kinds of multiaxial structures found in U monopnictides and Mn intermetallics on the basis of wave vector k point symmetry and configuration of the unit cell.

Citations

... The bulk intermetallic exhibits various stoichiometries as for example CeAg, CeAg 2 , CeAg 3 or Ce 3 Ag as well as a variety of different lattice structures [136][137][138][139][140][141][142]. CeAg for example exhibits a cubic structure with a lattice constant of a = 3.733 Å, but undergoes a transition to a tetragonal symmetry at T s = 16 K [136,137]. ...
... Actually, the value of J varies following changes either of the interaction distance [11, 12] (e.g. due to the substituent ion having a different radius), or of the band occupancy [18] (e.g. due to nonisovalent substitutions). ...