S. H. Devare

Quadrupole interaction of117In in Zn metal

We have used the TDPAC method to measure the temperature dependence of the quadrupole interaction frequencyvQ of117In in Zn lattice. The observedvQ reduces from 187.4 (20) MHz at 77°K to 155.3 (20) MHz at 673°K. The variation ofvQ is seen to be proportional toT3/2.

Preferential site occupancy of 111In in RNi5 compounds (R = rare earth)

Abstract We studied the site occupancy of 111 In diffused in RNi 5 compounds. From the measured EFG and asymmetry parameter in RNi 5 and Er 0.8 In 0.2 Ni 5 compounds we conclude that 111 In preferentially occupies the rare-earth site. This conclusion is further substantiated by a lattice sum calculation based on a point charge model.

Anomalous probe dependent quadrupole interaction observed in rare-earth cubic laves phase compounds RAl2

Abstract Quadrupole interaction at 111Cd probe in cubic alloys RAl2 is found to increase over the series compared to a decrease at Al on the same lattice site. This anomalous behaviour is attributed to strain-like effect at the probe. The electronic enhancement factor K are found to be smaller than for pure metals.

Sensing cerium valence by dilute impurity probes in intermetallic compounds

The QI frequencyvQ for99Ru in CeRu2 and ThRu2 differed very much from that for other RRu2 compounds with 3+ rare earth, while such a difference was not observed for a111Cd probe. The Ru charge calculated to fit the data for the99Ru probe is 1.59 while in the case of111Cd data, it is 1.63. It is shown that the apparent insensitivity of111Cd to the 3+ and 4+ valence is due to the corresponding lattice contributions being almost equal in magnitude though opposite in sign.

Kondo-like behaviour of microscopic susceptibility of Ce in RRhIn (R = Y, La, Ce, Gd)

Strong reduction in the local susceptibility was observed at low temperature at 140Ce in RRhIn (R = Y, La, Ce, Gd) compounds. The observed trend of the paramagnetic enhancement factor β could be reproduced for CeRhIn using the Kondo model modified for J ⩾ 1 with a characteristic temperature T0 ≃ 400 K.

Quadrupole interaction at181Ta in tellurium

The quandrupole interaction at181Ta in tellurium measured at various temperatures revealed two unique sites with an axially symmetric electric field gradient. These are interpreted as a near substitutional site with almost octahedral symmetry and a pure interstitial site in the tellurium lattice. The temperature dependence observed for QI frequencies corresponding to these sites supports this conclusion.

The quadrupole interaction at181Ta in Zn

The quadrupole interaction (QI) in hexagonal close packed zinc lattice was measured using the 482 keV, 10.6 ns probe state of181Ta employing the time-differential perturbed angular correlation technique. The electric field gradient (EFG) at181Ta in Zn was derived from the measured quadrupole interaction frequency at room temperature asVzz=12.202×1017 V/cm2. The quadrupole interaction measured at various temperatures displayed normal temperature dependence similar to that seen by this probe in many non-cubic hosts.

TDPAC measurement of quadrupole interaction at 111 Cd in the nearly heavy fermion system USn 2.9

Quadrupole interaction at111Cd probe has been studied in the nearly heavy fermion system USn3−δ using the TDPAC method. We observe a large quadrupole interaction frequency withvQ=89.9(10) MHz at 300 K which is much higher than the earlier reported result. The observed frequency shows a linear temperature dependence in the range 25–300 K.

Electric field gradient at100Rh in HCP zirconium and gadolinium

The measurement of QI frequencies at100Rh in Zr and Gd reveal that the electronic contribution to the EFG is quite large. The value of ¦K¦ is ∼8 for100RhZr whereas it is ≅45 for100RhGd. The temperature variation of100RhZr neither follows T1.5 nor has a linear T dependence.

Mössbauer effect studies of Sm(Rh1−xFex)3B2, x=0.005

Sm(Rh1−xFex)3B2 compound (x=0.005) was studied by57Fe Mossbauer spectroscopy as a function of temperature. The Fe doped compound has high temperature magnetic transition Tc*≅580 K in addition to the transition at Tc≅90 K exhibited by the pure SmRh3B2 compound. For T<Tc* the spectrum comprises of a quadrupole doublet along with magnetic splitting which merges into a single quadrupole doublet above Tc*. The results indicate that Fe induces a large polarization in the Rh-4d band due to the enhanced density of states at the Fermi level in the presence of the hybridized Sm 4f-electrons.