The first-principles full potential linear augmented plane-wave calculations of the electronic structure and hyperfine fields have been performed for ${\mathrm{CeIn}}_3$ compound in the antiferromagnetic phase. Cerium $4f$ states, positioned at the Fermi level, have been treated inside the valence panel, interacting with the other valence states. The calculated values of hyperfine fields both at Ce and In sites are found to be in reasonable agreement with the lowest-temperature measurements. The $4f$ orbital contribution dominates the magnetic hyperfine field (MHF) at the Ce sites. The contact field is negligible due to an almost complete cancellation of valence and core contributions. A nonzero MHF appears at In sites despite the fact that no net magnetic moment is induced and the vector sum of the nearest-neighbor Ce magnetic moments is zero. The $5p$ subshells of In are spin polarized due to the hybridization with the extended Ce valence states. This polarization is essential for the appearance of a small MHF at the In nucleus, which has mostly a spin-dipolar character. The $5p$ shell of In is also responsible for the presence of an electric-field gradient (EFG) at In nucleus in ${\mathrm{CeIn}}_3.$ The $5p$ subshell polarization, however, does not influence this EFG as it is developed mainly in the region closer to the nucleus, where the spin “up” and spin “down” $5p$ subshells show no difference.

The magnetic behavior of the intermetallic compound NdMn₂Ge₂ was investigated by bulk magnetization measurements and measurements of hyperfine interactions using perturbed γ–γ angular correlation (PAC) spectroscopy. Magnetization measurements indicate the presence of four magnetic transitions associated with the Mn and Nd magnetic sublattices. At high temperatures, magnetic measurements show a change in the slope of the magnetization due to an antiferromagnetic transition around T_N ∼ 425 K and a well defined ferromagnetic transition at T_C ∼ 320 K. Moreover, at ∼210 K a peak is observed in the magnetization curve, which is assigned to the reorientation of the Mn spin, and at ∼25 K an increase in the magnetic moment is also observed, which is ascribed to the ordering of Nd ions. PAC measurements using ¹⁴⁰La(¹⁴⁰Ce) and ¹¹¹In(¹¹¹Cd) probe nuclei allowed the determination of the temperature dependence of the magnetic hyperfine field (B_hf) at Nd and Mn sites, respectively. PAC results with ¹¹¹Cd probe nuclei at Mn sites show that the dependence of B_hf with temperature follows the expected behavior for the host magnetization associated with the magnetic ordering of Mn ions. From these results, the antiferromagnetic transition followed by a ferromagnetic ordering is clearly observed. PAC results with ¹⁴⁰Ce probe nuclei at Nd sites, however, showed a strong deviation from the Brillouin function, which is attributed to the Ce 4f-electron contribution to B_hf.

A local study of the influence of annealing temperature that can provoke structural defects and chemical disorder on the magnetism of Heusler alloys has been carried out by measuring hyperfine interactions in ${\mathrm{Pd}}_2\mathrm{Mn}Z$ ($Z=\mathrm{Ge}$ , In, Sn, and Sb). Perturbed angular correlation method has been used to measure the hyperfine fields at ${}^{111}\mathrm{Cd}$ probe nuclei substituting the Mn and $Z$ sites as a function of temperature. The fraction of ${}^{111}\mathrm{In}$ -nuclei-occupying Mn sites was found to increase with the annealing of sample at higher temperatures followed by quenching that can leave the alloy in a disordered state. As a consequence, it was possible to observe the effect of temperature in the ordering of the alloys. Moreover, electric quadrupole interaction measurements clearly indicated chemical disorder after quenching in ${\mathrm{Pd}}_2\mathrm{Mn}\mathrm{Sn}$ and an improvement in the ordering of the ${\mathrm{Pd}}_2\mathrm{Mn}\mathrm{Ge}$ structure at high temperatures.

In this paper, the effect in structural and magnetic properties of iron doping with concentration of 20% in hafnium dioxide (HfO₂) nanoparticles is investigated. HfO₂ is a wide band gap oxide with great potential to be used as high-permittivity gate dielectrics, which can be improved by doping. Nanoparticle samples were prepared by sol-gel chemical method and had their structure, morphology, and magnetic properties, respectively, investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with electron back scattering diffraction (EBSD), and magnetization measurements. TEM and SEM results show size distribution of particles in the range from 30 nm to 40 nm with small dispersion. Magnetization measurements show the blocking temperature at around 90 K with a strong paramagnetic contribution. XRD results show a major tetragonal phase (94%).

In this paper, we investigate the solubility effects of Co in ZnO (Zn_1−xCo_xO, where x = 0, 0.03, 0.05, 0.1, 0.2, 0.25, 0.4, 0.8, and 1) by combining the results of perturbed angular correlation (PAC) spectroscopy using highly diluted ¹¹¹Cd as probe nuclei and ab initio calculations based on spin-density functional theory (SDFT). This combined approach enables us to characterize the local structure around Cd ions, where, through PAC technique, it was possible to measure the EFG as a function of temperature and Co concentration and thereby monitor the changes in the structure and the Co solubility threshold in ZnO and the ZnO/CoO/Co₃O₄ mixed phase. The full-potential linear augmented plane wave plus local orbital (APW+lo) formalism were used here to describe the electronic structure of the supercells, including the atomic relaxations. These Ab initio calculations show an interesting behavior of the Cd and Co impurity levels in the band structure of ZnO, which explains the experimental results in terms of the origin of EFG and the evidence of ferromagnetic response.