Single Source Precursor for PAD-LaMnO₃ Thin Films

Abstract

A new lanthanum and manganese ethylenediaminetetraacetate (EDTA) coordination polymer (EDTA4− = [(CH2N)2(CH2-COOH)(CH2COO)4]) was synthesized from La(NO3)3 and Mn(NO3)2 reagents, ethylenediaminetetraacetic acid, and water at room temperature. The structure of the new compound formed, [{La2Mn3(EDTA)3(H2O)11}·12H2O]n, was determined by the single crystal X-ray diffraction technique. The synthesis and characterization of the La(III) and Mn(II) coordination complex, characterized by FTIR spectroscopy, thermogravimetry, and differential thermal analysis of the complex, are envisaged. X-ray crystal structure determination indicates that seven- and four-coordinate modes between La(III)/Mn(Π) and H4EDTA exist. [{La2Mn3(EDTA)3(H2O)11}·12H2O]n crystallizes in the monoclinic space group C2 with unit cell parameters of a = 16.1227(17) Å, b = 14.8049(16) Å, c = 14.8736(16) Å, and β = 116.107(2)°. Using this precursor, LaMnO3 (LMO) epitaxial thin films were grown by the polymer-assisted deposition (PAD) method on (100)SrTiO3 (STO) single crystalline substrates at a temperature of 900 °C. The LMO crystallized films exhibit a (001)LMO/(001)STO out-of-plane epitaxial relationship and a smooth surface morphology.

Keywords

• crystal structure
• thin films
• EDTA
• thermal analysis