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.