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Published on: February 5, 2022
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MnCaTa2O7-A Magnetically Ordered Polar Phase Prepared via Cation Exchange
Subhadip Mallick1, Fabio Orlandi2, Pascal Manuel2
1Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, UK.
Chemistry of Materials : a Publication of the American Chemical Society
|October 2, 2023
Summary
The synthesis of MnCaTa2O7 reveals a polar antiferromagnetic phase with lattice anomalies. Unlike related materials, it lacks weak ferromagnetism, highlighting the impact of cation order on ferroelectric properties.
Area of Science:
- Solid State Chemistry
- Materials Science
- Crystallography
Background:
- Pseudo-Ruddlesden-Popper phases are precursors to complex oxide materials.
- Layered perovskites with polar distortion modes are of interest for ferroelectric applications.
- Understanding structure-property relationships in transition metal tantalates is crucial.
Purpose of the Study:
- To synthesize and characterize a new Mn-containing layered perovskite, MnCaTa2O7.
- To investigate its magnetic and structural properties, particularly its polar and magnetic ordering.
- To compare its behavior with related MnATa2O7 phases to understand structure-property correlations.
Main Methods:
- Solid-state reaction synthesis.
- Magnetic susceptibility measurements.
- Neutron diffraction analysis.
- Analysis of lattice parameters and polar distortion modes.
Main Results:
- MnCaTa2O7 was synthesized as a polar phase (P21nm) with a distorted layered perovskite structure.
- Antiferromagnetic ordering was observed below TN = 56 K, with significant lattice anomalies and polar mode enhancement at TA = 50 K.
- Unlike MnSrTa2O7, MnCaTa2O7 did not exhibit weak ferromagnetism or magnetoelectric coupling.
Conclusions:
- The observed physical properties of MnCaTa2O7 are strongly influenced by Mn cation order and TaO6 tilting schemes.
- Subtle structural variations in hybrid improper ferroelectrics can lead to significant differences in distortion-mode couplings and emergent phenomena.
- The absence of magnetoelectric coupling in MnCaTa2O7, contrasting with related phases, underscores the sensitivity of these materials to structural details.
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