Magnetization, specific heat, 17ONMR, and 237Np Mössbauer study of U0.15Np0.85O2

We report a study of the magnetic and electronic properties of the U0.15Np0.85O2 solid solution, based on dc- and ac magnetization, 237Np Mössbauer spectroscopy, 17O nuclear magnetic resonance, and specific heat measurements. The compound orders antiferromagnetically at TN = 17 K. The different techniques reveal the complexity of this system with: (i) a spatial distribution of ordered moments, (ii) a small Np ordered moment (μNp = 0.3μB), and (iii) an additional specific heat anomaly at 7.4 K, with a residual value at very lowtemperature and a reduced magnetic entropy. The results are compared to the endmembers of the series,UO2 andNpO2, as well as to the other solid solutions previously reported in this system.We discuss how the properties of U0.15Np0.85O2 add input to the trend previously reported for the series in view of the models that have been proposed.

MARTEL Laura;  HEN Amir;  TOKUNAGA Yo;  KINNART Francois;  MAGNANI Nicola;  COLINEAU Eric;  GRIVEAU Jean-Christophe;  CACIUFFO Roberto; 

2018-12-06

AMER PHYSICAL SOC

JRC110936

2469-9950 (online),   

https://publications.jrc.ec.europa.eu/repository/handle/JRC110936,   

10.1103/PhysRevB.98.014410 (online),