Nuclear quadrupole interaction studies of C15 RMn{sub 2} hydrides (R=Y,Gd,Tb,Dy)
- Helmholtz Institut fuer Strahlen-und Kernphysik, University of Bonn, Nussallee 14-16, D-53115 Bonn (Germany)
- Steinmann-Institut fuer Geologie, Mineralogie und Palaeontologie, University of Bonn, Poppelsdorfer Schloss, D-53115 Bonn (Germany)
The nuclear electric quadrupole interaction (QI) of the probe nucleus {sup 111}In/{sup 111}Cd in the paramagnetic phase of the C15 rare earth (R)-manganese hydrides (deuterides) RMn{sub 2}H(D){sub x}, with R=Y, Gd, Tb, and Dy, has been investigated by perturbed angular-correlation spectroscopy. The QI between the {sup 111}Cd quadrupole moment and the electric-field gradient (EFG) at the probe nucleus on the Mn site has been measured as a function of temperature in TbMn{sub 2}H(D){sub x} in the concentration range 0{<=}x{<=}4.3 and in RMn{sub 2}H(D){sub x}, R=Y,Gd,Dy at the highest H content of x{approx}4.3. The relative temperature dependence of the EFG in the parent compounds RMn{sub 2} is twice as strong as in isostructural RAl{sub 2} which can be related to differences in the Debye temperatures resulting from different radius ratios r{sub R}/r{sub Mn} and r{sub R}/r{sub Al}[Joseph-Gschneidner postulate, Scr. Metall.2, 631 (1968)]. Hydrogenation of RMn{sub 2} increases the magnitude of the EFG by a factor of 2 between x=0 and x=4.3 but leaves the relative temperature dependence almost unchanged. Only at concentrations x>3.6 the temperature coefficient of the QI is significantly larger than in uncharged RMn{sub 2}. These results are compared with the much stronger concentration dependence and the anomalous temperature dependence of the QI of {sup 111}Cd in the C15 hydrides HfV{sub 2}H{sub x}. Evidence for an exceptionally high H mobility in TbMn{sub 2}H{sub x} is presented. The measurements provide information on structural changes and magnetic ordering temperatures at different H concentrat0010io.
- OSTI ID:
- 21192433
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 78, Issue 10; Other Information: DOI: 10.1103/PhysRevB.78.104202; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CADMIUM 111
CRYSTAL STRUCTURE
DEBYE TEMPERATURE
DEUTERIDES
HYDROGENATION
INDIUM 111
ISOTOPE RATIO
MANGANESE COMPOUNDS
MANGANESE HYDRIDES
PARAMAGNETISM
PERTURBED ANGULAR CORRELATION
QUADRUPOLE MOMENTS
QUADRUPOLES
RARE EARTHS
SPECTROSCOPY
TEMPERATURE COEFFICIENT
TEMPERATURE DEPENDENCE
TERBIUM COMPOUNDS