Complex magnetism of lanthanide intermetallics unravelled

We explain a profound complexity of magnetic interactions of some technologically relevant gadolinium intermetallics using an ab-initio electronic structure theory which includes disordered local moments and strong $f$-electron correlations. The theory correctly finds GdZn and GdCd to be simple ferromagnets and predicts a remarkably large increase of Curie temperature with pressure of +1.5 K kbar$^{-1}$ for GdCd confirmed by our experimental measurements of +1.6 K kbar$^{-1}$. Moreover we find the origin of a ferromagnetic-antiferromagnetic competition in GdMg manifested by non-collinear, canted magnetic order at low temperatures. Replacing 35\% of the Mg atoms with Zn removes this transition in excellent agreement with longstanding experimental data.Comment: 11 pages, 4 figure

Magnetic and magnetocaloric properties of DyCo2Cx alloys

The magnetic and magnetocaloric properties of DyCo2Cx (x = 0, 0.05, 0.1, and 0.15) alloys were investigated. The results show that the Curie temperature (TC) of the DyCo2Cx alloys increases with increasing C content, from 136 K (x = 0) to 152 K (x = 0.15), but the lattice parameter a of DyCo2Cx exhibits a maximum at x = 0.05. The suppression of the ac susceptibility of DyCo2Cx at low temperature indicates the enhancement of the domain wall pinning effect by carbon doping. The positive slops of the Arrott plots of the doped compounds indicate that the phase transition is second order for the carbon-doped alloys, and the maximum value of the isothermal magnetic entropy change (ΔSM) for the magnetic field change of 50 kOe decreases from −13.9 J/kg· K (x = 0) to −7.8 J/kg·K (x = 0.15). The relative cooling power (RCP) of DyCo2Cx is nearly the same in all studied alloys, while the temperature-averaged entropy change over 10 K temperature span, TEC(10), indicates decreasing magnetocaloric performance of carbon doped materials

ЗМІНИ ІМУННОГО СТАТУСУ У ДІТЕЙ, ХВОРИХ НА ЗАЛІЗОДЕФІЦИТНУ АНЕМІЮ.

The thesis deais with the study of immunity dates in chiidren 3-14 years of age with iron deficiency anemia depending on age, severity state, the disease duration and associated pathoiogy.В работе дан анализ даных литературы по показателях иммунитета у детей сжелезодефицитной анемией в зависимости от возраста, степени тяжести,продолжительности'заболевания'и'фоновой'патологии.В роботі проведений аналіз даних літератури по показниках імунітету у дітей, хворих на залізодефіцитну анемію у залежності відвіку, ступеня тяжкості, тривалості захворювання та фонової'патології

Magnetocaloric effect of gadolinium in high magnetic fields

International audienceThe magnetocaloric effect of gadolinium has been measured directly in pulsed magnetic fields up to 62 T. The maximum observed adiabatic temperature change is T ad = 60.5 K, the initial temperature T 0 being just above 300 K. The field dependence of T ad is found to follow the usual H 2/3 law, with a small correction in H 4/3. However, as H is increased, a radical change is observed in the dependence of T ad on T 0 , at H = const. The familiar caret-shaped peak situated at T 0 = T C becomes distinctly asymmetric, its high-temperature slope becoming more gentle and evolving into a broad plateau. For yet higher magnetic fields, μ 0 H 140 T, calculations predict a complete disappearance of the maximum near T C and an emergence of a new very broad maximum far above T C

Crystal structure, magnetic properties, and the magnetocaloric effect of Gd5Rh4 and GdRh

The crystal structures of Gd5Rh4 and GdRh have been studied by powder and single crystal x-ray diffraction. The results show that Gd5Rh4 is isotypic with Pu5Rh4 and the bond length of the short Rh-Rh dimer is 2.943(4) Å. According to heat capacity measurements in zero magnetic field, the magnetic ordering temperature of Gd5Rh4 is 13 K, in agreement with magnetization measurements. Both the heat capacity peak shape and the positive slope of the Arrott plots at Curie temperature (TC) indicate the second-order nature of the magnetic transition. The temperature dependence of magnetization of Gd5Rh4 measured in 1 kOe applied field indicates noncollinear magnetic ordering that may change into nearly collinear ferromagnetic ordering by increasing the magnetic field. GdRh is ferromagnetic below T C  = 22 K. Moderate magnetocaloric effects and relatively high refrigerant capacities are observed in Gd5Rh4 and GdRh

Magnetocaloric effect of gadolinium in high magnetic fields

The magnetocaloric effect of gadolinium has been measured directly in pulsed magnetic fields up to 62 T. The maximum observed adiabatic temperature change is Delta T-ad = 60.5 K, the initial temperature T-0 being just above 300 K. The field dependence of Delta T-ad is found to follow the usual H-2/3 law, with a small correction in H-4/3. However, as H is increased, a radical change is observed in the dependence of Delta T-ad on T-0, at H = const. The familiar caret-shaped peak situated at T-0 = T-C becomes distinctly asymmetric, its high-temperature slope becoming more gentle and evolving into a broad plateau. For yet higher magnetic fields, mu H-0 greater than or similar to 140 T, calculations predict a complete disappearance of the maximum near T-C and an emergence of a new very broad maximum far above T-C