Regensburg 2019 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 34: Methods in Computational Materials Modelling (methodological aspects, numerics)
MM 34.7: Talk
Thursday, April 4, 2019, 12:00–12:15, H44
Electric Field Gradient in Ca3Mn2O7 — Pedro Rodrigues1, Ivan Miranda2, Samuel Santos1,2, Armandina Lopes1, Gonçalo Oliveira1, Lucy Assali2, João Pedro Araujo1, and •Helena Petrilli2 — 1Faculdade de Ciências, Universidade do Porto,Porto, Portugal — 2Instituto de Física, Universidade de São Paulo, São Paulo, Brazil
Naturally layered perovskites, such as the Ruddlesden-Popper phases or A-site ordered double perovskites have appeared as a fascinating route in exploring the design and achievement of nonexpensive room temperature multiferroic materials. In these, distortions of the lattice such as octahedron rotation and tilting modes, couple to polar cation dislocation modes, inducing cation ordering and a spontaneous ferroelectric polarization, a mechanism known as hybrid improper ferroelectricity. Here, several structural, charge and magnetic phase transitions of Ca3Mn2O7 is studied by combining theoretical and experimental methods, in order to provide a tool to unravel its local electronic and magnetic properties. The theoretical approach is performed using ab-inito electronic structure calculations, in the framework of the Density Functional Theory (DFT); measurements are performed for structural characterization as well as magnetic and hyperfine quantities. Through this comparison, a local scenario of the complex behavior is this class of systems is studied. By inspecting electric field gradients at the nuclei obtained via theoretical calculations and inferred from Perturbed Angular Correlations (PAC) measurements at a Cd probe, trends are obtained and the application of the proposed procedure is discussed .