Centrosymmetry Breaking and Ferroelectricity Driven by Short-Range Magnetic Order in the Quadruple Perovskite (YMn3)Mn4O12.
Inorg Chem
; 58(20): 14204-14211, 2019 Oct 21.
Article
em En
| MEDLINE
| ID: mdl-31593448
ABSTRACT
By means of single-crystal X-ray diffraction, we give direct crystallographic evidence of a centrosymmetry breaking below TS = 200 K, concomitant with the onset of a commensurate structural modulation in the quadruple perovskite YMn3Mn4O12. This result, which explains the anomalously large thermal coefficient of the Y3+ ion in previously reported structural models, is attributed to the small size of the Y3+ ion, which causes its underbonding within the dodecahedral coordination polyhedron. The present data are consistent with a commensurate superstructure described by an I-centered pseudo-orthorhombic cell with polar Ia symmetry and a ≈ aFâ2 = 10.4352(7) Å, b ≈ 2bF = 14.6049(9) Å, c ≈ cFâ2 = 10.6961(7) Å, and ß = 90.110(3)°, where aF ≈ cF ≈ 7.45 Å, bF ≈ 7.34 Å, and ß ≈ 91° are the unit cell parameters of the I2/m structure observed at room temperature. Consistent with the above polar structure, at lower temperature, T* = 70 K, we observe in polycrystalline samples an anomaly of the direct current (DC) and alternating current (AC) magnetization, concomitant with the appearance of a net electric polarization, as indicated by pyrocurrent and dielectric constant measurements. These results, complemented by electrical transport measurements, suggest a magnetic ferroelectricity driven by short-range magnetic order in YMn3Mn4O12.
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01-internacional
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MEDLINE
Idioma:
En
Revista:
Inorg Chem
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
França