Metal–Insulator Transition and Magnetic Properties of La1−xEuxNiO3 (0≤x≤1)

✍ Scribed by R.D. Sánchez; M.T. Causa; A. Seoane; J. Rivas; F. Rivadulla; M.A. López-Quintela; J.J. Pérez Cacho; J. Blasco; J. Garcı́a

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 256 KB
• Volume: 151
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8590

✦ Synopsis

This paper reports X-ray di4raction patterns, Rietveld 5t pro5les, electrical resistivity dc magnetic susceptibility, and electron paramagnetic resonance (EPR) measurements of La 1+x Eu x NiO 3 (04x41). A shift to high temperature of the metal}insulator transition temperature with x and hysteresis in the electrical resistivity and magnetization versus temperature at intermediate concentration of the compound are observed. The antiferromagnetic order of the Ni sublattice can be observed after subtracting the magnetic contribution of the rare earth ions. A change in space group from R-3c to Pbnm for x50.4 was detected, as was the appearance of magnetic order. Samples with 1% Gd 3؉ probe were studied by EPR. Drastic changes were observed in the shape of the lines with x, though the crystal 5eld symmetry of the Gd sites remained constant in all the samples studied. We observed that when Eu substitution increases, the number of Gd ions that contribute to the crystal-5eld spectrum diminishes. A possible cause of this e4ect is a previously reported increase in the Ni+O covalence in the neighborhood of the Eu sites.