# New $La_2CuO_4$ Derivatives $La_{2-2x}Sr_{2x}Cu_{1-x}M_xO_4 (M5Ti, Mn, Fe, or Ru)$: A Study of Linear Cu–O–M Electronic Interaction in Two Dimensions

Ramesha, K and Uma, S and Vasanthacharya, NY and Gopalakrishnan, J (1997) New $La_2CuO_4$ Derivatives $La_{2-2x}Sr_{2x}Cu_{1-x}M_xO_4 (M5Ti, Mn, Fe, or Ru)$: A Study of Linear Cu–O–M Electronic Interaction in Two Dimensions. In: Journal of Solid State Chemistry, 128 (2). pp. 169-175.

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## Abstract

Oxides of the general formula $La_{2-2x}Sr_{2x}Cu^{II}_{1-x} 1M^{IV}O_4 (M = Ti, Mn, Fe, or Ru)$, crystallizing in the tetragonal $K_2NiF_4$ structure, have been synthesized. For M = Ti, only the x = 0.5 member could be prepared, while for M = Mn and Fe, the composition range is $0<x\leq 0.5$, and for M5Ru, the composition range is 0<x40.5. There is no evidence for an ordering of Cu(II) and M(IV) in the x = 0.5 members. While the members of the M = Ti, Mn, and Ru series are semiconducting/insulating, the members of the M = Fe series are metallic, showing a broad metal–semiconductor transition around 100 K for $0<x \leq 0.15$ that is possibly related to a $Cu(II)–O–Fe(IV)\leftrightarrowCu(III)– O–Fe(III)$ valence degeneracy. Increasing the strontium content at the expense of lanthanum in $La_{2-2x}Sr_{2x}Cu_{1-x}Fe_xO_4$ for $x\leq0.20$ renders the samples metallic but not superconducting.

Item Type: Journal Article Copyright of this article belongs to Elsevier. Division of Chemical Sciences > Solid State & Structural Chemistry Unit 19 Feb 2007 19 Sep 2010 04:35 http://eprints.iisc.ernet.in/id/eprint/9860