Predicting room-temperature multiferroic phase of NaLaFeMO6 (M = Ru, Re, Os) with strong magnetoelectric coupling

Abstract

Discovering multiferroic materials is one of the most important questions for facilitating devices based on the electric field control of magnetism. The great challenge is to create room temperature multiferroic materials with strongly coupled ferroelectric and ferromagnetic (or ferrimagnetic) orderings. Here we present simple, chemically intuitive design rules to identify a class of bulk magnetoelectric materials based on the “bicolor” layering of P21 double ferrimagnetic perovskites, e.g., NaLaFeMO6 (M = Ru, Re, Os). Using density functional theory calculations, we elucidated the origin of the ferroelectricity and show that it is a general consequence of the layering of any bicolor P21 double ferrimagnetic perovskites. Our calculations showed that the ferroelectric polarization is up to several μC/cm2 and the net magnetic moments are 3, 2, and 3 μB for NaLaFeRuO6, NaLaFeReO6, and NaLaFeOsO6, respectively in these proposed materials. More importantly, we highlighted the existence of a low-energy ferroelectric switching path, along which the magnetization is also likely reversed, evidencing the strong magnetoelectric coupling existing in this system. In addition, the critical temperature of polarization and magnetization are both well above room temperature. It is expected that this work can encourage the designing and experimental implementation of a large class of strong magneto-electric multiferroic materials with large magnetization and electric polarization above room temperature.