Open AccessPerturbed angular correlation investigation of the electric field gradient at 181Ta probe in the Hf2Ni7 compound
Author(s) -
C. Petrović,
B. Cekić,
A. Umićević,
Rongwei Hu,
B. David,
Tanja Barudžija
Publication year - 2012
Publication title -
nuclear technology and radiation protection
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.31
H-Index - 16
eISSN - 1452-8185
pISSN - 1451-3994
DOI - 10.2298/ntrp1202095c
Subject(s) - electric field gradient , quadrupole , electric field , diffraction , materials science , magnetization , analytical chemistry (journal) , magnetic field , crystallite , atmospheric temperature range , spectral line , field (mathematics) , condensed matter physics , nuclear magnetic resonance , chemistry , atomic physics , optics , physics , thermodynamics , metallurgy , mathematics , quantum mechanics , chromatography , astronomy , pure mathematics
The perturbed angular correlation method was employed to study the temperature dependence of electric field gradients at the 181Ta probe in the polycrystalline Hf2Ni7 compound. The temperature evolution of the sample content was measured using high-temperature X-ray diffraction. To check the magnetic order of the sample, magnetization measurements and additional perturbed angular correlation measurements with externally applied magnetic field were performed. All obtained spectra showed no evidence of magnetic order of the Hf2Ni7 phase. Within the experimental resolution of the apparatus, the measured electric field gradients at 181Ta probe for the two inequivalent 181Hf/181Ta sites in the Hf2Ni7 compound appeared as one in the range of 78-944 K. A single quadrupole interaction implies that the electric field gradients at the two Hf sites must be quite similar. At 293 K, the measured quadrupole interaction parameters are νQ = 433(1) MHz and η = 0.300(4). An increase of the quadrupole frequency and a gradual rising of the asymmetry parameter were observed with increasing temperature. The high-temperature X-ray diffraction indicated a build up of HfO2 above 693 K