Substitutional effect of Mg²⁺ on structural and magnetic properties of La₂Mg_xNi_1‐xMnO₆ double‐perovskite thin films

Abstract

By doping different concentrations of Mg2+ at Ni site, the (00l)‐oriented La2MgxNi1‐xMnO6 (abbreviated as LMxNMO, x = 0, 0.1, 0.2, 0.3, 0.4) double‐perovskite thin films were epitaxially grown by pulsed laser deposition. The substitutional effect of Mg2+ on the structural and magnetic properties of the films is comprehensively investigated. It is found that with the increase of Mg‐doping concentration, the in‐plane and out‐of‐plane lattice constants as well as the cell volume of the LMxNMO thin films increase, which could be ascribed to the radius difference between Mg2+ and Ni2+/Ni3+ ions, resulting in the in‐plane compressive stress in LMxNMO films. When the Mg‐doping concentration is small (x ≤ 0.1), the doped Mg2+ tends to substitute Ni3+, which restrains the intensity of antiferromagnetic interaction between Ni3+‐O‐Mn3+, resulting in the reduced the exchange bias field as well as the increased the saturation magnetization. However, when the Mg‐doping concentration increases to x ≥ 0.2, Mg2+ becomes to mainly replace Ni2+ position, which could inhibit the super‐exchange ferromagnetic interaction between Ni2+‐O‐Mn4+ magnetic paths and thus reduce the saturation magnetization. The enhanced magnetic properties can be obtained in the LM0.1NMO double‐perovskite thin film, with a large saturation magnetization of 492.12 emu/cm3 and a high Curie temperature of 262.7 K.

Colossal Ferroelectric Photovoltaic Effect in Inequivalent Double-Perovskite Bi2FeMnO6 Thin Films

“…You et al reported the polarization order engineering of La-doped BFO thin films, which enhanced the PV effect through the strong coupling of lattice, polarization, and electron orbitals. The combined effect of Sm element substitution and substrate strain engineering not only increased the magnetic transition temperature ( T C ) of the BMO multiferroic films, but also enlarged the deposition window. , Wang et al incorporated Mg 2+ ions at the B-site of La 2 Mg x Ni 1– x MnO 6 thin films, which led to enhanced ionic ordering and ferromagnetic interactions through modification of the lattice parameter and chemical valence. A-site alkaline earth substitution can also modify the properties of BFO, but larger ionic radii and lower valence states tend to cause heterogeneous phases and lattice defects.…”