title: Synthesis and characterization of pure and doped (Na, Ca, Sr) nanograined LaMnO3 magnetoresistive ceramics.
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 1273 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 (Tc) and magnetoresistivity properties of the samples were measured by a Superconducting Quantum Interference Device (SQUID). The decrease in the resistivity below Tc occurred in a much wider range of temperature compared to ceramics having micron-size grains.
authors.affiliation: Department of Physical Chemistry, University of Pavia, Vie Taramelli 16 1-27100 Pavia, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Maglia
authors.forename: L
authors.initials: L
authors.lastname: Malavasi
authors.forename: H E
authors.initials: HE
authors.lastname: Camurlu
authors.forename: A
authors.initials: A
authors.lastname: Tacca
authors.forename: G
authors.initials: G
authors.lastname: Chiodelli
authors.forename: G
authors.initials: G
authors.lastname: Spinolo
authors.forename: M C
authors.initials: MC
authors.lastname: Mozzati
authors.forename: U
authors.initials: U
authors.lastname: Anselmi-Tamburini
authors.forename: Z A
authors.initials: ZA
authors.lastname: Munir