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Title: The crystal structure and electrical properties of K{sub 2}NiF{sub 4}-type (Ca{sub 2−x}Sm{sub x})MnO{sub 4}

Graphical abstract: The relationship between log ρ of K{sub 2}NiF{sub 4}-type (Ca{sub 2−x}Sm{sub x})MnO{sub 4} and 1000/T. - Highlights: • K{sub 2}NiF{sub 4}-type (Ca{sub 2−x}Sm{sub x})MnO{sub 4} was synthesized using a polymerized complex route. • The semiconductive samples had minimum values of ρ and E{sub a} at x = 0.1. • The log ρ–1/T curve of x = 0.3 consisted of two different lines at 315 K. • The 1/χ − T curve of x = 0.3 had a peak at 325 K. • These results indicated the presence of a charge-ordering transition at x = 0.3. - Abstract: K{sub 2}NiF{sub 4}-type (Ca{sub 2−x}Sm{sub x})MnO{sub 4} (0.02 ≤ x ≤ 0.3) was synthesized using a polymerized complex route. The crystal structure changed from tetragonal to orthorhombic at x = 0.3. A variation in the lattice parameters was explained by the Mn–O(2) distance, the Mn−O(2)−Mn angle, and the (Ca,Sm)–(Ca,Sm) distance. The samples were n-type semiconductors, and the minimum values of electrical resistivity (ρ) and an energy gap (E{sub g}) at x = 0.1 were accounted by electron transfer through an Mn−O(2)−Mn path and overlap between the Mnt{sub 2g} and Op{sub π} orbitals. In the sample (x = 0.3), the log ρ–1000/Tmore » curve consisted of two different lines that intersected at ca. 325 K, and a peak was observed at ca. 315 K in the magnetic susceptibility–temperature curve. These results indicated the presence of a charge-ordering (CO) transition at 315–325 K.« less
Authors:
 [1] ;  [2] ; ;  [3]
  1. The Graduate School of Natural Science and Technology (Science), Okayama University, 3-1-1 Tsushima-Naka, Kita-Ku, Okayama 700-8530 (Japan)
  2. Osaka Municipal Technical Research Institute, 1-6-50 Morinomiya, Jyoto-Ku, Osaka 536-8553 (Japan)
  3. Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, Kyo-Tanabe 610-0321 (Japan)
Publication Date:
OSTI Identifier:
22475737
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 64; Other Information: Copyright (c) 2015 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; CALCIUM COMPOUNDS; CARBON MONOXIDE; CRYSTAL STRUCTURE; ELECTRIC CONDUCTIVITY; ENERGY GAP; LATTICE PARAMETERS; MAGNETIC SUSCEPTIBILITY; MANGANATES; ORTHORHOMBIC LATTICES; PERMANGANATES; SAMARIUM COMPOUNDS; SEMICONDUCTOR MATERIALS; X-RAY DIFFRACTION