The huge effect of Mn substitution on the structural and magnetic properties of LaFeAsO: the La(Fe, Mn)AsO system. (21st December 2018)

• Record Type: Journal Article
• Authors: Martinelli, A; Manfrinetti, P; Provino, A; Ritter, C; Ferdeghini, C
• Is Part Of: Journal of physics. Volume 31:Number 6(2019)
• Publication Date: 2018-12-21
• Subjects: LaFeAsO -- Mn-doping -- neutron diffraction -- phase diagram -- Fe-based superconductors; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aaf597
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The substitution of Mn for Fe on the sub-lattice in LaFeAsO has a remarkable impact on both structural and magnetic properties; for example, the structural and magnetic transition temperatures decrease of ~20 K in samples with a Mn-content as low as x = 0.01. Such a dramatic effect results from the high stability of the substituting Mn 2+ ion (3 d 5 ) in its high-spin state, which opposes any variation to its electronic state (configuration), perturbing thereby interactions within the Fe sub-lattice between the Fe ions surrounding the substituent. Several investigations ascertained that the structural transformation in Ln FeAsO compounds ( Ln : lanthanide) cannot be ascribed to lattice degrees of freedom, but rather to electronic or spin ones. In this context, even an extremely low concentration of Mn 2+ ions diluted in the Fe sub-lattice produces a reduction of the electronic degree of freedom of the system, thus hindering the structural transformation and the magnetic transition.