Exploring the magnetic percolation threshold in the improper ferroelectric Sr3Sn2O7 upon Cr and Fe-doping

Blasco, J. ; Cuartero, V. (Universidad de Zaragoza) ; Lafuerza, S. ; Gracia, D. ; Rodríguez-Velamazán, J.A. ; Puente-Orench, I. ; Subías, G.

Resumen: We examine the effect of Fe and Cr substitutions at the Sn site on the magnetic properties of the hybrid improper ferroelectric Sr3Sn2O7. Upon co-doping with La to preserve the electric charge balance in the unit cell, the Sr3-xLaxSn2-xCrxO7, Sr3-xLaxSn2-xFexO7 and Sr2LaSnFe1-yCryO7 series can be obtained as single phases up to x = 1 and for all y values. The unit cell volume is isotropically reduced with doping, so that the orthorhombic structure is preserved. However, these substitutions strongly destabilize the ferroelectric order by decreasing the transition temperature, TFE, below room temperature for x ≥ 0.25. La/Cr co-doping is unable to induce long-range magnetic and compositions from this series behave as conventional paramagnetic compounds; although for high doping concentration (x ≥ 0.5), the significant deviations from the Curie law at low temperatures suggest the onset of antiferromagnetic correlations. In the case of La/Fe co-doping, all samples show strong antiferromagnetic correlations, but a spin glass-like behavior is observed for x ≈ 1 compounds. Finally, no long-range magnetic ordering is observed in La/Cr-Fe co-doped samples, but at the same time an increase in spontaneous magnetization is seen at low temperature, which is associated with the presence of competitive magnetic interactions, in particular the Fe-O-Cr superexchange ferromagnetic interaction. The lack of long-range magnetic order in the investigated series of Cr/Fe-doped Sr3Sn2O7, indicates that the critical concentration of magnetic atoms necessary to overcome the magnetic percolation threshold exceeds the 50 % in magnetic cations in these bilayered Ruddlesden-Popper perovskites.

Idioma: Inglés

DOI: 10.1016/j.materresbull.2025.113385

Año: 2025

Publicado en: Materials Research Bulletin 187 (2025), 113385 [11 pp.]
ISSN: 0025-5408

Financiación: info:eu-repo/grantAgreement/ES/AEI/CEX2023-001286-S
Financiación: info:eu-repo/grantAgreement/ES/DGA/E11-23R
Financiación: info:eu-repo/grantAgreement/ES/DGA/E12-23R
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2021-124734OB-C21

Tipo y forma: Article (Published version)

Área (Departamento): Área Cienc.Mater. Ingen.Metal. (Dpto. Ciencia Tecnol.Mater.Fl.)