Growth, Structure and Properties of La_2-xSr_xNiO₄ (x= 0 to 0.3) Single Crystals

Abstract

Large, homogeneous single crystals of La 2- x Sr x NiO 4 ( x =0, 0.1, 0.2, 0.3) of 7 mm in diameter and 20 mm in length have been obtained by using a lamp-image type floating-zone furnace under oxygen atmosphere. The chemical and X-ray diffraction analyses reveal the presence of excess oxygen with a presumed form of peroxide ion in the crystals of x =0 and 0.1. Small magnetic susceptibility and obvious deviation from the Curie-Weiss law are observed, whereas the diamagnetic signals from superconductivity are not detected on heating from 4 K to 300 K. The resistivity is semiconductive at room temperature and becomes insulative below 100 K.