We present the results of polarized and unpolarized inelastic neutron scattering measurements of the heavy-fermion superconductor UBe13 at 10 K. At this temperature, the energy spectrum of the magnetic scattering is characterized by a broad quasielastic Lorentzian line shape modified by the Bose occupation factor, with a width of 132 meV (half-width at half maximum). No evidence of a narrow (few meV) f-level resonance predicted by the electronic specific-heat coefficient is observed. The energy-integrated magnetic scattering yields a susceptibility which is consistent with bulk measurements, indicating that any additional response must have a small spectral weight. © 1986 The American Physical Society.

Inelastic neutron scattering from the antiferromagnetic (TN=9.7 K) heavy-fermion system U2Zn17 reveals magnetic fluctuations which are highly localized in reciprocal space and broad in frequency. At higher energies, the fluctuations persist almost unchanged to temperatures well above Tn. Analysis of the neutron and bulk susceptibility data in terms of Kondo-type single-ion response functions modified by Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between ions indicates that it is the temperature dependence anticipated theoretically of the effective RKKY coupling which drives the magnetic phase transition in U2Zn17. © 1987 The American Physical Society.

The results of neutron-diffraction measurements are reported which confirm that superconducting TmRh4B4 orders magnetically at TM0.7 K. The modulated antiferromagnetic structure deduced from the data is of particular interest, considering the similarity of certain other physical properties of TmRh4B4 to those of the ferromagnetic, reentrant superconductor ErRh4B4. © 1983 The American Physical Society.

Neutron scattering measurements were performed on polycrystalline samples of UBe13 in order to establish more accurately the structure and probe the dynamics of the spin fluctuations. The structure was confirmed to be cubic with space group O6h (Fm3c) with BeII positional parameters y = 0.1763(1) and z = 0.1150(1). The inelastic spectrum at T = 10 K exhibits a broad response with half width at half maximum of 15 meV. © 1985.

The results of neutron-diffraction measurements are reported which confirm the development of long-range magnetic order in superconducting NdRh4B4. Two distinct antiferromagnetic transitions occur below the superconducting phase-transition temperature TSC=5.4 K, one at TMH 1.5 K and the other at TML 1.0 K. In both phases, the body-centered tetragonal sublattice of Nd atoms orders antiferromagnetically with the Nd3+ moments aligned along the unique c axis. The magnetic moment is modulated sinusoidally along the [100] direction in the higher-temperature magnetic phase and along the [110] direction in the lower-temperature phase. The measured saturation moment is 3.4± 0.5μB. No ferromagnetic component could be detected in the higher-temperature magnetic phase within an experimental sensitivity of 0.3μB. © 1982 The American Physical Society.

The phase transition of U2Zn17 at 9.7 K has been investigated by neutron powder diffraction. The transition corresponds to the onset of antiferromagnetic order where the U moments are oriented antiparallel to their nearest neighbors within the basal planes and the near neighbor along the c^ axis of this rhombohedral compound. At 5 K, the ordered moments lie within the basal planes and are of magnitude (0.8±0.1)1/4B, which is substantially below the paramagnetic moment of 2.251/4B/U atom given by high-temperature susceptibility data. © 1986 The American Physical Society.

Small-angle neutron experiments show that near the transition from superconductor to ferromagnet in ErRh4B4 scattering peaks occur at a wave vector |q's|=0.06 -1. The temperature and wave-vector dependence suggest this signal is due to oscillatory magnetization fluctuations caused by the electromagnetic coupling of magnetic and superconducting order parameters. The ferromagnetic Bragg scattering shows a 5% hysteresis and transition-temperature-smearing effects which are also due to magnetic-superconducting interactions. © 1980 The American Physical Society.

A new family of rare earth-rhodium-tin intermetallic compounds, with the representative formula (RE)RhxSny, has been synthesized in single crystal form. The compounds containing the heavier rare earths are superconducting and those with the lighter rare earths are generally magnetic. The compound ErRh1.1Sn3.6 exhibits reentrant superconductivity with Tc = 0.97 K and Tm = 0.57 K as determined from ac magnetic susceptibility measurements. The synthesis and X-ray characterization of the series are described and the results of electrical resistivity, upper critical magnetic field, magnetic susceptibility, specific heat and neutron scattering measurements on the Er compound are given. © 1980.