Effect of B-Site Ordering on the Magnetic Order in Multifunctional La_2NiMnO_6 Double Perovskite

To obtain various Ni/Mn orderings, we use a low-temperature synthesized method to modulate the Ni/Mn ordering of the ferromagnetic-ferroelastic La_2NiMnO_6 compound, and the Ni/Mn ordering is estimated by the low-temperature saturation magnetism. The microstructures, crystal structures and magnetic properties are investigated, and the Landau theory are used to describe the form and magnitude of the coupling effects between Ni/Mn ordering and magnetic order parameters. It is predicted that the Ni/Mn ordering would be a strong coupling effect with the Curie transition temperatures if the La_2NiMnO_6 sample stoichiometry is close.