Exploring a route to induce ferromagnetism on Sr3Sn2O7 by co-doping with non-Jahn-Teller-distorted Mn3+ and La3+ cations
We here explore a route to induce a ferromagnetic ground state on the Ruddlesden-Popper phases Sr3-xLaxSn2-xMnxO7 replacing Sn by Mn up to x = 1.25. Samples with low Mn concentration (x ≤ 0.1) adopt the polar A21am space group, consistent with previously reported ferroelectric behavior. For higher M...
| Autores: | , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/413446 |
| Acceso en línea: | http://hdl.handle.net/10261/413446 |
| Access Level: | acceso abierto |
| Palabra clave: | Multiferroics Improper ferroelectricity Cluster-glass EXAFS |
| Sumario: | We here explore a route to induce a ferromagnetic ground state on the Ruddlesden-Popper phases Sr3-xLaxSn2-xMnxO7 replacing Sn by Mn up to x = 1.25. Samples with low Mn concentration (x ≤ 0.1) adopt the polar A21am space group, consistent with previously reported ferroelectric behavior. For higher Mn concentrations (x ≥ 0.25) the samples adopt the centrosymmetric space group Amam due to the suppression of specific rotational modes. X-ray absorption spectroscopy confirmed the presence of a Mn3+ ion in all samples though it is not Jahn-Teller distorted. An undistorted MnO6 octahedral local structure is reported instead, with Debye-Waller factors for the Mn-O bond length increasing as Mn content does, due to the disorder induced in the Sn/Mn sublattice and the rising of rumpling distortions (expansion of the perovskite bilayer coupled with shrinkage of the rock salt layer). All the Sr3-xLaxSn2-xMnxO7 samples exhibit ferromagnetic correlations. While Mn³ ⁺ cations in low Mn-content samples (x ≤ 0.25) agree with spin-only contributions, higher doping levels deviate from this interpretation, possibly due to the enhancement of magnetic interactions. At 5 K, all samples exhibit spontaneous magnetization which increases with Mn content, but the Mn³ ⁺ magnetic sublattice is not fully polarized. Neutron diffraction confirmed the absence of long-range magnetic order and AC susceptibility analysis indicates a cluster-glass magnetic state due to structural disorder and competing interactions. Compared to simple perovskites, our results indicate that the rock salt layer plays a key role in suppressing long-range ferromagnetic order, making it particularly challenging to achieve multiferroic behavior by doping hybrid improper ferroelectrics with magnetic cations. |
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