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'Nuclear quadrupole double resonance' in keywords
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1996 (1)
1994 (1)
1Author    O. Tte R, K. K., Ze Lm, G. M., Je Rb, A. SeegeraRequires cookie*
 Title    Investigation of Intrinsic Point Defects in Metals by Nuclear Quadrupole Double Resonance  
 Abstract    The paper reviews the principal features of the Nuclear Q uadrupole D ouble Resonance (N Q D O R) technique, with particular emphasis on its application to the investigation o f imperfec­ tions in cubic metals. N Q D O R permits measurements o f the electric field gradients (EFG) at quadrupole-m oment-carrying nuclei in the neighbourhood of point defects and thus to obtain "fingerprints" of these defects. An N Q D O R facility set-up at the M ax-Planck-Institut für M etall­ forschung in Stuttgart is described. It has been used to study the intrinsic defects introduced into Cu and dilute Cu/Be alloys by low-temperature irradiation with electrons or protons or by cold-work. It is shown that all well-resolved irradiation-induced EFG observed in the present work are due to one kind o f defect only, which is identified as the <100) dumbbell self-interstitial. When considered together with measurements of the electrical resistivity on the same specimens, the annealing be­ haviour of the N Q D O R lines supports the so-called two-interstitial model o f radiation damage in face-centred cubic metals rather than the one-interstitial model. 
  Reference    Z. Naturforsch. 49a, 47 (1994); received October 26 1993 
  Published    1994 
  Keywords    Nuclear quadrupole double resonance, Self-interstitials, Vacancies, Radiation dam ­ age, Intrinsic point defects in copper 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0047.pdf 
 Identifier    ZNA-1994-49a-0047 
 Volume    49 
2Author    K. Konzelmann, G. Majer, A. SeegerRequires cookie*
 Title    Solid Effect Between Quadrupolar Transitions in Dilute Cu-Pd Alloys  
 Abstract    The paper investigates the Dynamic Solid Effect (DSE) in Nuclear Quadrupole Double Reso-nance (NQDOR) on a system (dilute alloys of CuPd with 8, 42, 210, or 1000 at.ppm Pd) chosen for its simplicity and the possibility to test the theoretical concepts on which the experimental tech-niques (in particular the so-called Berthier-Minier technique for exhibiting the DSE) are based. NQDOR allows to observe the transitions between the Cu nuclear energy levels split by the quadrupolar interaction with the electric field gradients generated by nearby Pd atoms even in dilute alloys, in which the fraction of Cu nuclei experiencing a given field gradient is very small. The DSE permits transitions at frequencies corresponding to the sums or differences of quadrupolar level splittings at neighbouring nuclei and thus gives access to information on the spatial correlation of nuclei accessible to NQDOR studies. The DSE information is shown to be in full accord with the conclusions drawn earlier, on the basis of line-intensity arguments, on the assignment of quadrupo-lar transitions to the first four shells of Cu nuclei surrounding isolated Pd atoms but, in addition, allows to identify the low-frequency NQDOR lines associated with Cu nuclei in the fifth and sixth shells. 
  Reference    Z. Naturforsch. 51a, 506—514 (1996); received February 13 1996 
  Published    1996 
  Keywords    Nuclear quadrupole double resonance, Atomic defects in Cu, Electric field gradients, Solid effect 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0506.pdf 
 Identifier    ZNA-1996-51a-0506 
 Volume    51