Abstract:

The hexagonal YMnO3 (h-YMO) is one of the most studied magnetoelectric materials because of its suitability for usage in ferroelectric (FE) memories and due to the intriguing coexistence of ferroelectricity and magnetism. It has a high ferroelectric-paraelectric transition temperature (Tc ~ 1258 K), and a low antiferromagnetic (AFM) – paramagnetic (PM) transition temperature (Tn ~ 75 K). For T Andlt; Tn the h-YMO is simultaneously AFM and FE, exhibiting a clear magnetoeletric characteristic. The magnetism in this compound arises from Mn3+ ions, in 3d4 configuration, with high spin state, S = 2. Despite numerous investigation about of the h-YMO magnetic structure, it is still under debate in the literature [1-3]. In this work we performed a non-collinear spin density functional theory (DFT) study in order to obtain the magnetic ground state of the h-YMO compound. The calculations were carried out using a full potential linearized augmented plane wave method as embodied in the Elk computer code. With this computational tool, we could simulate all magnetic configurations described by the experiments for the h-YMO crystal with and without SOC interaction. The lowest energy was found to P6’3 magnetic structure when the SOC are present. Our results shown that the inclusions of the SOC interaction, in fact, give rise a small FM component along the c axis in agreement with previous experimental observation [3].