A new family of rare earth-rhodium-tin intermetallic compounds, with the representative formula (RE)Rh.sub.x Sn.sub.y, 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 ErRh.sub.1.1 Sn.sub.3.6 exhibits reentrant superconductivity with T.sub.c =0.97 K and T.sub.m =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.
A heat treatment method heats an oxide optical crystal in an oxygen atmosphere containing ozone to improve the light absorption characteristics of the oxide optical crystal so that the light absorption of the oxide optical crystal with light in wavelength bands other than light in wavelength bands with which the oxide optical crystal exerts the intrinsic absorption is reduced to the least possible extent. Guided-optical-wave propagation devices and optical devices, such as optical isolators, optical recording media and second harmonic generators, employing the oxide optical crystal having these improved absorption characteristics, operate at a high efficiency.
