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Title: Synthesis of manganite perovskite Ca{sub 0.5}Sr{sub 0.5}MnO{sub 3} nanoparticles in w/o-microemulsion

Abstract

In this paper, w/o-microemulsions were employed to produce nanoparticles of the perovskite Ca{sub 0.5}Sr{sub 0.5}MnO{sub 3}, which have a size of approximately 20-50 nm. The procedure was carried out using sodium hydroxide or ammonia as co-precipitation agent. The precursor was transformed to perovskite by calcinations at 580 deg. C. Nanosized particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N{sub 2} adsorption (BET)

Authors:
 [1];  [2]
  1. Department of Chemistry, TU Berlin, Sekr. TC 8, Strasse des 17. Juni 124, 10623 Berlin (Germany). E-mail: Lopez.Alejandra@chem.tu-berlin.de
  2. Department of Chemistry, TU Berlin, Sekr. TC 8, Strasse des 17. Juni 124, 10623 Berlin (Germany). E-mail: schomaecker@tu-berlin.de
Publication Date:
OSTI Identifier:
20891623
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 41; Journal Issue: 2; Other Information: DOI: 10.1016/j.materresbull.2005.08.015; PII: S0025-5408(05)00317-X; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ADSORPTION; AMMONIA; CALCINATION; CALCIUM OXIDES; CHEMICAL PREPARATION; COPRECIPITATION; MANGANESE OXIDES; MICROEMULSIONS; NANOSTRUCTURES; PEROVSKITE; PRECURSOR; SCANNING ELECTRON MICROSCOPY; SODIUM HYDROXIDES; STRONTIUM OXIDES; X-RAY DIFFRACTION

Citation Formats

Lopez-Trosell, Alejandra, and Schomaecker, Reinhard. Synthesis of manganite perovskite Ca{sub 0.5}Sr{sub 0.5}MnO{sub 3} nanoparticles in w/o-microemulsion. United States: N. p., 2006. Web. doi:10.1016/j.materresbull.2005.08.015.
Lopez-Trosell, Alejandra, & Schomaecker, Reinhard. Synthesis of manganite perovskite Ca{sub 0.5}Sr{sub 0.5}MnO{sub 3} nanoparticles in w/o-microemulsion. United States. doi:10.1016/j.materresbull.2005.08.015.
Lopez-Trosell, Alejandra, and Schomaecker, Reinhard. Thu . "Synthesis of manganite perovskite Ca{sub 0.5}Sr{sub 0.5}MnO{sub 3} nanoparticles in w/o-microemulsion". United States. doi:10.1016/j.materresbull.2005.08.015.
@article{osti_20891623,
title = {Synthesis of manganite perovskite Ca{sub 0.5}Sr{sub 0.5}MnO{sub 3} nanoparticles in w/o-microemulsion},
author = {Lopez-Trosell, Alejandra and Schomaecker, Reinhard},
abstractNote = {In this paper, w/o-microemulsions were employed to produce nanoparticles of the perovskite Ca{sub 0.5}Sr{sub 0.5}MnO{sub 3}, which have a size of approximately 20-50 nm. The procedure was carried out using sodium hydroxide or ammonia as co-precipitation agent. The precursor was transformed to perovskite by calcinations at 580 deg. C. Nanosized particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N{sub 2} adsorption (BET)},
doi = {10.1016/j.materresbull.2005.08.015},
journal = {Materials Research Bulletin},
number = 2,
volume = 41,
place = {United States},
year = {Thu Feb 02 00:00:00 EST 2006},
month = {Thu Feb 02 00:00:00 EST 2006}
}
  • We report the synthesis of the perovskite manganites Pr{sub 0.5}Sr{sub 0.5}MnO{sub 3} and Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3} using mild hydrothermal conditions. Both are formed as polycrystalline powders from solutions of metal salts in aqueous potassium hydroxide at 240 deg. C, and crystallise as a tetragonal polymorph (space group I4/mcm). Scanning electron microscopy shows both materials to contain cuboid-shaped crystallites several microns in dimension, and the average particle size is verified by light scattering measurements. We also report the first hydrothermal synthesis of 2H-BaMnO{sub 3} and 4H-SrMnO{sub 3}, and the first subcritical hydrothermal synthesis of CaMn{sub 2}O{sub 4} (marokite). Despite themore » formation of these alkali-earth manganese oxides at 240 deg. C, we have been unable to isolate rare-earth manganese oxides LnMnO{sub 3} using similar conditions. We discuss the formation of perovskite manganites in hydrothermal reactions by relating our new results to those manganites already reported to form under hydrothermal conditions, and rationalise the trends seen by considering tolerance factor of the perovskite and the variance of the A-site metal radius.« less
  • This article studies the intrinsic influence of hole doping (n=0.5+{delta}) on the structural and magnetic phases of the Pr{sub 0.5-{delta}}Ca{sub 0.2+{delta}}Sr{sub 0.3}MnO{sub 3} ceramic manganite. Neutron thermodiffractograms are reported for samples with n=0.46, 0.48, 0.50, 0.52, and 0.54 ({delta}=-0.04,-0.02,0.0,0.02,0.04) in the temperature range 10 K{<=}T{<=}300 K, as well as high-resolution neutron-diffraction experiments for selected samples and temperatures. We observe structural and magnetic phase coexistence for all the studied compositions and discuss the temperature evolution of the lattice parameters, phase fractions, and magnetic moments of the observed phases. For hole dopings n<(1/2), the ground state at low temperature is ferromagnetic, whilemore » for n>(1/2), it is CE-type antiferromagnetic with Mn{sup 3+} and Mn{sup 4+} spatial order. An extra A-type antiferromagnetic phase is also observed for n>(1/2). Our results clearly show the strong coupling between the structural phases and the macroscopic magnetic behavior of the system. The temperature dependence of the magnetization and the hole doping influence are discussed in terms of phase separation.« less
  • Structural study of orbital-ordered manganite thin films has been conducted using synchrotron radiation, and a ground state electronic phase diagram is made. The lattice parameters of four manganite thin films, Nd0.5Sr0.5MnO3 (NSMO) or Pr0.5Sr0.5MnO3 (PSMO) on (011) surfaces of SrTiO3 (STO) or [(LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7] (LSAT), were measured as a function of temperature. The result shows, as expected based on previous knowledge of bulk materials, that the films' resistivity is closely related to their structures. Observed superlattice reflections indicate that NSMO thin films have an antiferro-orbital-ordered phase as their low-temperature phase while PSMO film on LSAT has a ferro-orbital-ordered phase, and thatmore » on STO has no orbital-ordered phase. A metallic ground state was observed only in films having a narrow region of A-site ion radius, while larger ions favor ferro-orbital-ordered structure and smaller ions stabilize antiferro-orbital-ordered structure. The key to the orbital-ordering transition in (011) film is found to be the in-plane displacement along [011] direction.« less
  • We have carried out a systematic magnetic relaxation study, measured after applying and switching off a 5 T magnetic field to polycrystalline samples of La{sub 0.5}Ca{sub 0.5}MnO{sub 3} and Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3}. The long time logarithmic relaxation rate (LTLRR), decreased from 10 to 150 K and increased from 150 to 195 K in La{sub 0.5}Ca{sub 0.5}MnO{sub 3}. This change in behavior was found to be related to the complete suppression of the antiferromagnetic phase above 150 K and in the presence of a 5 T magnetic field. At 195 K, the magnetization first decreased, and after a few minutesmore » increased slowly as a function of time. Moreover, between 200 and 245 K, the magnetization increased throughout the measured time span. The change in the slope of the curves, from negative to positive at about 200 K was found to be related to the suppression of antiferromagnetic fluctuations in small magnetic fields. A similar temperature dependence of the LTLRR was found for the Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3} sample. However, the temperature where the LTLRR reached the minimum in Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3} was lower than that of La{sub 0.5}Ca{sub 0.5}MnO{sub 3}. This result agrees with the stronger ferromagnetic interactions that exist in Nd{sub 0.5}Sr{sub 0.5}MnO{sub 3} in comparison to La{sub 0.5}Ca{sub 0.5}MnO{sub 3}. The above measurements suggested that the general temperature dependence of the LTLRR and the underlying physics were mainly independent of the particular charge ordering system considered. All relaxation curves could be fitted using a logarithmic law at long times. This slow relaxation was attributed to the coexistence of ferromagnetic and antiferromagnetic interactions between Mn ions, which produced a distribution of energy barriers.« less
  • Two new compounds Ca{sub 0.5}Bi{sub 3}V{sub 2}O{sub 10} and Sr{sub 0.5}Bi{sub 3}V{sub 2}O{sub 10} have been synthesized in the ternary system: MO-Bi{sub 2}O{sub 3}-V{sub 2}O{sub 5} system (M=M{sup 2+}). The crystal structure of Sr{sub 0.5}Bi{sub 3}V{sub 2}O{sub 10} has been determined from single crystal X-ray diffraction data, space group P1-bar and Z=2, with cell parameters a=7.1453(3)A, b=7.8921(3)A, c=9.3297(3)A, {alpha}=106.444(2){sup o}, {beta}=94.088(2){sup o}, {gamma}=112.445(2){sup o}, V=456.72(4)A{sup 3}. Ca{sub 0.5}Bi{sub 3}V{sub 2}O{sub 10} is isostructural with Sr{sub 0.5}Bi{sub 3}V{sub 2}O{sub 10}, with, a=7.0810(2)A, b=7.8447(2)A, c=9.3607(2)A, {alpha}=106.202(1){sup o}, {beta}=94.572(1){sup o}, {gamma}=112.659(1){sup o}, V=450.38(2)A{sup 3} and its structure has been refined by Rietveld methodmore » using powder X-ray data. The crystal structure consists of infinite chains of (Bi{sub 2}O{sub 2}) along c-axis formed by linkage of BiO{sub 8} and BiO{sub 6} polyhedra interconnected by MO{sub 8} polyhedra forming 2D layers in ac plane. The vanadate tetrahedra are sandwiched between these layers. Conductivity measurements give a maximum conductivity value of 4.54x10{sup -5} and 3.63x10{sup -5}Scm{sup -1} for Ca{sub 0.5}Bi{sub 3}V{sub 2}O{sub 10} and Sr{sub 0.5}Bi{sub 3}V{sub 2}O{sub 10}, respectively at 725 deg. C.« less