TY - JOUR
T1 - Substitutional effects of 3d transition metals on the magnetic and structural properties of quasi-two-dimensional La5Mo4O16
AU - Ramanujachary, K. V.
AU - Lofland, S. E.
AU - McCarroll, W. H.
AU - Emge, T. J.
AU - Greenblatt, M.
AU - Croft, M.
N1 - Funding Information:
We acknowledge with pleasure the assistance of Project SEED scholars, Lyndon Stephenson, Jessica Ding, and Josephine Gerlaye, in some of the synthesis and analysis. K.V.R. acknowledges the support from Research Corporation (CC4366) and Rowan University through an award of a separately budgeted research grant. The work by W.H.M. and M.G. was supported by NSF Solid State Chemistry Grant DMR-99-07963.
PY - 2002
Y1 - 2002
N2 - Substituted phases with the composition La5Mo4-xTxO16-δ (T = Co, Fe, Mn, and Mg and x ≁ 0.7) were prepared by fused-salt electrolysis and/or conventional solid-state methods. The crystal structure of the parent compound, La5Mo4O16, contains perovskite-like corner-sharing MoO6 octahedral units in the ab plane separated by Mo2O10 bioctahedral units along the c direction. Detailed single-crystal X-ray diffraction studies on the Co-substituted phase, La5Mo3.31Co0.69O16-δ, indicated that the unit cell is triclinic (space group C-1) with Co exclusively replacing Mo atoms in the perovskite layers. X-ray absorption measurements revealed that the transition metal ions are divalent, consistent with the crystal structure analysis. The anomalous magnetic transition observed at 180 K in the parent compound shifts to lower temperatures upon substitution with transition metal ions. No long-range magnetic order was evident in the Mg2+-substituted compositions. The electrical resistivity of all the substituted phases was at least 3 orders of magnitude higher than that of the parent compound. Variations in the magnetic and electrical properties have been ascribed to the disruption of exchange correlations caused by substitutional disorder at the Mo sites.
AB - Substituted phases with the composition La5Mo4-xTxO16-δ (T = Co, Fe, Mn, and Mg and x ≁ 0.7) were prepared by fused-salt electrolysis and/or conventional solid-state methods. The crystal structure of the parent compound, La5Mo4O16, contains perovskite-like corner-sharing MoO6 octahedral units in the ab plane separated by Mo2O10 bioctahedral units along the c direction. Detailed single-crystal X-ray diffraction studies on the Co-substituted phase, La5Mo3.31Co0.69O16-δ, indicated that the unit cell is triclinic (space group C-1) with Co exclusively replacing Mo atoms in the perovskite layers. X-ray absorption measurements revealed that the transition metal ions are divalent, consistent with the crystal structure analysis. The anomalous magnetic transition observed at 180 K in the parent compound shifts to lower temperatures upon substitution with transition metal ions. No long-range magnetic order was evident in the Mg2+-substituted compositions. The electrical resistivity of all the substituted phases was at least 3 orders of magnitude higher than that of the parent compound. Variations in the magnetic and electrical properties have been ascribed to the disruption of exchange correlations caused by substitutional disorder at the Mo sites.
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U2 - 10.1006/jssc.2001.9448
DO - 10.1006/jssc.2001.9448
M3 - Article
AN - SCOPUS:0036330773
VL - 164
SP - 60
EP - 70
JO - Journal of Solid State Chemistry
JF - Journal of Solid State Chemistry
SN - 0022-4596
IS - 1
ER -