Soft antiphase tilt of oxygen octahedra in the hybrid improper multiferroic Ca3Mn1.9Ti0.1O7

Article

关键词: TOTAL-ENERGY CALCULATIONS;    AUGMENTED-WAVE METHOD;    X-RAY-DIFFRACTION;    WEAK FERROMAGNETISM;    LAYERED PEROVSKITE;    BASIS-SET;    CRYSTAL;    FERROELECTRICITY;    CA3MN2O7;    NEUTRON;   

DOI  :  10.1103/PhysRevB.97.041112

来源: SCIE

【 摘 要 】

We report a single crystal neutron and x-ray diffraction study of the hybrid improper multiferroic Ca3Mn1.9Ti0.1O7 (CMTO), a prototypical system where the electric polarization arises from the condensation of two lattice distortion modes. With increasing temperature (T), the out-of-plane, antiphase tilt of MnO6 decreases in amplitude while the in-plane, in-phase rotation remains robust and experiences abrupt changes across the first-order structural transition. Application of hydrostatic pressure (P) to CMTO at room temperature shows a similar effect. The consistent behavior under both T and P reveals the softness of antiphase tilt and highlights the role of the partially occupied d orbital of the transition-metal ions in determining the stability of the octahedral distortion. Polarized neutron analysis indicates the symmetry-allowed canted ferromagnetic moment is less than the 0.04 mu(B)/Mn site, despite a substantial out-of-plane tilt of the MnO6 octahedra.

【 授权许可】

Free