Low-temperature heat capacity and magnetism in (U1−yLny)O2 and (U1−yAmy)O2 (y = 0.01 − 0.05) solid solutions: Effects of substitution and self-irradiation

Autor: Griveau, Jean-Christophe, Vigier, Jean-François, Popa, Karin, Vălu, Sorin-Octavian, Colineau, Eric, Konings, Rudy J. M.
Předmět:
Zdroj: Journal of Applied Physics; 11/14/2022, Vol. 132 Issue 18, p1-13, 13p
Abstrakt: The low-temperature heat capacity of lanthanide-doped (La, Nd) and americium-doped UO 2 samples was measured by calorimetry. The results showed a strong effect on the antiferromagnetic C p anomaly as a result of crystal lattice substitution, defects resulting from self-irradiation, and electron interaction. It was found that the substitution of trivalent ions ( La 3 + , Nd 3 + , Am 3 + ) leads to a split of the λ peak, for which we hypothesize that the clustering of the trivalent ions with the charge compensator pentavalent U 5 + can play a role. The overall behavior is confirmed by magnetization measurements using SQUID. The observed differences between La 3 + , Nd 3 + , and Am 3 + are attributed to the f – f exchange interaction. 241 Am decay causes in addition self-irradiation effects (point defects), and reduces Néel temperature, peak intensity, and magnetic entropy as a function of decay (accumulated α dose). The observed effects are similar to 238 Pu-doped UO 2 , the slight differences being attributed to a higher degree of disorder in the Am material. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index