The magnetic and neutron diffraction studies of La{sub 1−x}Sr{sub x}MnO{sub 3} nanoparticles prepared via molten salt synthesis

Journal Article · Thu Jan 15 00:00:00 EST 2015 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2014.10.024· OSTI ID:22443520

Kačenka, M. ^[1]; Jirák, Z.; Maryško, M.; Veverka, P.; Veverka, M. ^[2]; Vratislav, S. ^[3]

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1. Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic)
2. Institute of Physics, AS CR, Cukrovarnická 10, 162 00 Praha 6 (Czech Republic)
3. Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Břehová 7, 115 19 Praha 1 (Czech Republic)

Series of single-phase La{sub 1−x}Sr{sub x}MnO{sub 3} nanoparticles (x=0.25−0.47) with the size of about 50 nm was prepared in molten NaNO{sub 2}. TEM evidenced well dispersed particles that are not interconnected by sintering bridges in contrast to traditional products. Interestingly, some reduction of the perovskite cell volume, particularly at higher Sr-contents, was detected by XRD. Moreover, reduced magnetization and decreased Curie temperature in comparison to sol–gel samples were observed. Neutron diffraction analysis of the as-prepared nanoparticles and several comparative samples with x=0.37 indicated that the anomalous behavior of studied particles probably originate in the overdoped outer shell. The overdoping might result from both the surface oxygen chemisorption and from an increased Sr concentration in the shell. By all means, the overdoping would lead to compressive surface stress, driving the x=0.37 ground state toward a mixture of FM and A-type AFM ordering as observed by neutron diffraction. - Graphical abstract: La{sub 1−x}Sr{sub x}MnO{sub 3} nanoparticles with the size of about 50 nm were prepared by newly established method in molten NaNO{sub 2}. TEM proved the formation of well-separated particles without sintering bridges, the major advantage over traditional preparation methods. - Highlights: • Series of La{sub 1−x}Sr{sub x}MnO{sub 3} nanoparticles was prepared by novel method in NaNO{sub 2} melt. • Lower magnetization and Curie temperature in comparison to sol–gel nanoparticles was observed. • Overdoping of outer shell was indicated by neutron diffraction and cerimetric titration. • Overdoping shifts La{sub 0.37}Sr{sub 0.63}MnO{sub 3} ground state to a mixture of FM and A-type AFM ordering.

• OSTI ID: 22443520
• Journal Information: Journal of Solid State Chemistry, Vol. 221; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ATOMIC FORCE MICROSCOPY
CHEMISORPTION
CURIE POINT
GROUND STATES
MAGNETIZATION
MIXTURES
MOLTEN SALTS
NANOPARTICLES
NEUTRON DIFFRACTION
NITRITES
OXYGEN
PEROVSKITE
SINTERING
SODIUM COMPOUNDS
STRESSES
SYNTHESIS
TITRATION
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION