The magnetic hyperfine field at 181Ta in SmFe2 was measured by the TDPAC method in the temperature range from 80 K up to the Curie point. It was shown to rise from 7.1(2) T at 80 K to 8.4(1) T at 300 – 400 K. The results are compared with those for other RFe2 Laves phases (R = Y, Nd, Gd, Lu).

AbstractThe time‐differential perturbed angular correlation (TDPAC) of the 133–482 keV γ‐ray cascade in 181Ta in the intermetallic compound Hf2Fe is measured in the temperature range 78 to 903 K. At 78 K the following parameters of the electric field gradient (EFG) at the two unequivalent Hf sites are obtained: V = (1.91 ± 0.14) × 1022 V/m2, η(1) = 0.505(7); V = (1.05 ± 0.2) × 1021 V/m2, η(2) = 0 (fixed parameter). Discontinuities in the temperature dependence of the EFG parameters at T ≈︁ 600 K are observed as well as an indication at the possible existence of the third Hf site above 600 K.

The hyperfine magnetic fields for181Ta in the cubic (C 15) Laves phases LuFe2 and GdFe2 have been measured by the TDPAC method. At 300 K, Bhf=−20.5(4) T for LuFe2 and +19.0(5) T and +10.2(4) T for the samples of GdFe2, prepared at normal and high (7.7 GPa) pressure, have been obtained. Temperature dependence of these fields in the range 77–900 K has been also measured.

Results of TDPAC studies of hyperfine interaction in high temperature superconducting ceramics are reported. The γ-ray cascade of 329–487 keV in140Ce excited in the decay of140La in La2-xSrxCuO4 samples (x=0 and 0.15), and 133–482 keV cascade in181Ta excited in the decay of181Hf in YBa2Cu3O7-δ samples were used. The procedure of introducing radioactive181Hf into the ceramics is described and indirect evidence for the occupation of Cu sites by the181Hf-181Ta probe is presented.

The hyperfine magnetic fields for181Ta in the cubic (C 15) Laves phases LuFe2 and GdFe2 have been measured by the TDPAC method. At 300 K, Bhf=−20.5(4) T for LuFe2 and +19.0(5) T and +10.2(4) T for the samples of GdFe2, prepared at normal and high (7.7 GPa) pressure, have been obtained. Temperature dependence of these fields in the range 77–900 K has been also measured.

The hyperfine magnetic field at 181Ta in the ferromagnetic intermetallic Laves compound (Y0.97Hf0.03) Fe2 is measured by the perturbed angular correlation method. A value Hhf(Ta) = –14.4 T is obtained at 300 K. The temperature dependence of this field, measured in the range from 78 K up to and above, the Curie point, is shown to be different from that of the bulk magnetization. [Russion Text Ignored]

The hyperfine magnetic fields at181Ta and57Fe in the ferromagnetic Laves intermetallic compounds (ZrxHf1−x)Fe2 (0≤x≤1) have been measured by the methods of TDPAC and Mössbauer effect, respectively, and shown to be practically independent of x at x≥0.4. An average value Bhf (Ta)=−6.52 T at 300 K was obtained for samples with x≥0.4, and −14.2 T for pure HfFe2 in the hexagonal C14 modification. For 0<x<0.4, a superposition of both field components was observed. A deviation of the temperature dependence of Bhf(Ta) in (Zr0.9 Hf0.1)Fe2 from that for Bhf (Fe) and the bulk magnetization was confirmed, studied in detail, and shown to exist for all x≥0.4. The temperature dependence of Bhf(Ta) in HfFe2 was close to that of Bhf (Fe).

physica status solidi (a)Volume 73, Issue 2 p. K299-K302 Short Note Pressure Dependence of the Hyperfine Magnetic Field at 181Ta in the Intermetallic Compound (Zr0.5Hf0.5)Fe2 Z. Z. Akselrod, Z. Z. Akselrod Institute of Nuclear Physics, Moscow State University Search for more papers by this authorB. A. Komissarova, B. A. Komissarova Institute of Nuclear Physics, Moscow State University Search for more papers by this authorL. N. Kryukova, L. N. Kryukova Institute of Nuclear Physics, Moscow State University Search for more papers by this authorA. A. Opalenko, A. A. Opalenko Institute of Nuclear Physics, Moscow State University Search for more papers by this authorG. K. Ryasny, G. K. Ryasny Institute of Nuclear Physics, Moscow State University Search for more papers by this authorA. A. Sorokin, A. A. Sorokin Institute of Nuclear Physics, Moscow State University Search for more papers by this author Z. Z. Akselrod, Z. Z. Akselrod Institute of Nuclear Physics, Moscow State University Search for more papers by this authorB. A. Komissarova, B. A. Komissarova Institute of Nuclear Physics, Moscow State University Search for more papers by this authorL. N. Kryukova, L. N. Kryukova Institute of Nuclear Physics, Moscow State University Search for more papers by this authorA. A. Opalenko, A. A. Opalenko Institute of Nuclear Physics, Moscow State University Search for more papers by this authorG. K. Ryasny, G. K. Ryasny Institute of Nuclear Physics, Moscow State University Search for more papers by this authorA. A. Sorokin, A. A. Sorokin Institute of Nuclear Physics, Moscow State University Search for more papers by this author First published: 16 October 1982 https://doi.org/10.1002/pssa.2210730276Citations: 7 117234 Moscow, USSR. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume73, Issue216 October 1982Pages K299-K302 RelatedInformation

TDPAC measurements for the 133–482 keV γ-ray cascade in181Ta were performed with181Hf sources in the ferromagnetic Laves intermetallic compound (Zr0.9Hf0.1)Fe2. Two samples, annealed and not annealed after activation of181Hf in a reactor, were investigated. It was shown that in the annealed sample practically all the181Ta daughters occupied regular sites in the cubic Zr(Hf) sublattice and experienced a unique magnetic hyperfine fieldHh.f.(Ta)=−6.38(14) T. In the unannealed source the regular precession was observed only for ≈50% of181Ta nuclei, another half of them were located at some “unobservable” sites due, obviously, to a recoil after the (n, γ) reaction. Possible reasons for discrepancies in the results onHh.f.(Ta) reported in the literature are discussed.