Iron based oxypnictides: Structure and properties

Metals, alloys and metal oxides have been investigated over several decades for their interesting electronic properties including superconductivity. However the pnictides (multinary compounds containing at least one pnictogen) have not been so popular for their superconducting properties. That has changed recently (2008) after the discovery of superconductivity at 26 K in fluoride-doped LaO0.9F0.1FeAs by Kamihara et al. [1] which has created a huge excitement in the field of superconductivity and pnictides. Since then a large number of pnictogen based superconductors were discovered. This article summarizes the structure and properties of the parent compounds, LnOFePn (Ln = La, Ce and Pr; Pn = P and As). Effect of Fe–Pn hybridization on structural distortion, electronic and magnetic properties of LnOFePn is examined.

Graphical abstractStructure and properties of oxypnictides with general formula LnOFePn (Ln = rare earth; Pn = P and As) is reviewed. LnOFePn compounds crystallize in tetragonal ZrCuSiAs type structure at room temperature. LnOFeAs exhibit structural distortion on cooling while LnOFeP retain tetragonal structure at low temperature.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Structural aspects of Fe based oxypnictides. ► Electrical and magnetic properties of LnOFePn (Ln = rare earth; Pn = P and As). ► Fe–As hybridization in LnOFeAs (Ln = rare earth).