Synthesis and characterization of pure and doped (Na, Ca, Sr) nanograined LaMnO3 magnetoresistive ceramics

MAGLIA F., MALAVASI L., ÇAMURLU H. E., TACCA A., CHIODELLI G., SPINOLO G., ...More

JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, vol.8, no.2, pp.846-853, 2008 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 8 Issue: 2
  • Publication Date: 2008
  • Doi Number: 10.1166/jnn.2008.b116
  • Journal Name: JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.846-853
  • Keywords: lanthanum manganites, spark plasma sintering, nanograined ceramics, magneto-resistivity, PLASMA SINTERING/SYNTHESIS PROCESS, LOW-TEMPERATURE MAGNETORESISTANCE, LOW-FIELD MAGNETORESISTANCE, FUNDAMENTAL INVESTIGATIONS, COMBUSTION SYNTHESIS, GIANT MAGNETORESISTANCE, LANTHANUM MANGANITES, THIN-FILMS, CONSOLIDATION, PARTICLE
  • Akdeniz University Affiliated: Yes

Abstract

Pure and Na, Ca, and Sr doped lanthanum manganites (LaMnO3, La0.85Na0.15MnO3, La0.7Ca0.3 MnO3, La0.7Sr0.3MnO3) were prepared in form of bulk nano-structured materials through a two-step process. Nanometric powders were synthesized by the Pechini method and subsequently densified by Spark Plasma Sintering at 12,73 K for 5 minutes under a pressure of 140 MPa. The method allowed the preparation of single phase manganites with a theoretical density above 98% together with a very limited growth of the grain size. Grain sizes below 70 nm were obtained for all materials except La0.85Na0.15MnO3 which showed a much larger grain size. Curie temperatures (T-C) and magneto resistivity properties of the samples were measured by a Superconducting Quantum Interference Device (SQUID). The decrease in the resistivity below T-C occurred in a much wider range of temperature compared to ceramics having micron-size grains.

Pure and Na, Ca, and Sr doped lanthanum manganites (LaMnO3, La0.85Na0.15MnO3, La0.7Ca0.3 MnO3, La0.7Sr0.3MnO3) were prepared in form of bulk nano-structured materials through a two-step process. Nanometric powders were synthesized by the Pechini method and subsequently densified by Spark Plasma Sintering at 12,73 K for 5 minutes under a pressure of 140 MPa. The method allowed the preparation of single phase manganites with a theoretical density above 98% together with a very limited growth of the grain size. Grain sizes below 70 nm were obtained for all materials except La0.85Na0.15MnO3 which showed a much larger grain size. Curie temperatures (T-C) and magneto resistivity properties of the samples were measured by a Superconducting Quantum Interference Device (SQUID). The decrease in the resistivity below T-C occurred in a much wider range of temperature compared to ceramics having micron-size grains.