Synthesis, structure, and magnetism of T′-phase La2−xYxCuO4: Properties of the 214 T′-phase without magnetic rare earth elements

✍ Scribed by O Beom-hoan; R. Tian; J.T. Markert

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 145 KB
• Volume: 235-240
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(94)91499-0

✦ Synopsis

We report the synthesis, structure, and magnetic properties of magnetic-rare-earth-free T'-phase material La2_=YzCuO4. Synthesis of this metastable compound was attempted by three different techniques: 1) a solutionbased technique, starting from either oxides or nitrates, followed by low-temperature (<600"C) reaction; 2) highpressure, high-temperature synthesis (25 kbar, .,~1000*C); and 3) low-temperature synthesis (.,-400"C) in a KOH flux. The first technique yields single-phased T'-phase La2_=Y=CuO4materials over the range 0.10 < x < 0.80; high-pressure synthesis has been successful near x = 2, but not for lower values of x. La2_=Y=CuO4 is a minority phase product of the the flux technique. The solution-based technique yields smaller particle sizes than the flux technique. Magnetic measurements indeed reveal the behavior of the Cu magnetism, although the low temperature data for the solution-based samples are dominated by .,.8% Cu 2+ defects, more than typically encountered in other magnetic-rare-earth-free copper oxides. We observe a static susceptibility (corrected for core diamagnetism) of Xo = 1.3×10-4 cm3/mole. Attempts to dope these materials with Ce have not yet been successful.