Stabilization and study of SrFe(1-x)Mn(x)O2 oxides with infinite-layer structure

Area of Science:

• Materials Science
• Solid-State Chemistry
• Inorganic Chemistry

Background:

• Layered transition metal oxides are crucial for various electronic applications.
• Infinite-layer structures offer unique properties due to reduced dimensionality.
• Understanding the interplay of Fe and Mn in oxide lattices is key for tuning properties.

Purpose of the Study:

• To synthesize and characterize a series of layered strontium iron manganese oxides (SrFe(1-x)Mn(x)O(2)).
• To investigate the structural, electronic, and magnetic properties of these novel infinite-layer compounds.
• To explore the stabilization of divalent Fe and Mn in square-planar oxygen coordination.

Main Methods:

• Synthesis via chemical reduction of 3D perovskites using CaH(2) at 583 K.
• Structural characterization using neutron powder diffraction (NPD) and X-ray absorption spectroscopy.
• Magnetic property analysis through temperature-dependent NPD and magnetic moment determination.

Main Results:

• Successful synthesis of SrFe(1-x)Mn(x)O(2) (x = 0, 0.1, 0.2) with an infinite-layer structure.
• Fe and Mn confirmed to be in divalent oxidation states (Fe(2+), Mn(2+)) with distinct lattice stresses.
• Antiferromagnetic ordering observed with a Néel temperature (T(N)) above room temperature (453–523 K) for x = 0.2.
• Stabilization of Fe(2+) and Mn(2+) in square-planar oxygen coordination achieved.

Conclusions:

• The infinite-layer SrFe(1-x)Mn(x)O(2) oxides represent a novel class of materials with tunable magnetic properties.
• The selective removal of apical oxygen atoms leads to unique structural and electronic characteristics.
• These kinetically stable layered oxides reoxidize to perovskites in air at elevated temperatures.