Spin lattice and magnetoelectric coupling in Pb(Fe_1/2Nb_1/2)O₃ and Pb(Fe_2/3W_1/3)O₃

Crystal structure, spin-lattice and magneto-electric coupling were studied Pb(Fe_1/2Nb_1/2)O₃ (PFN), Pb(Fe_2/3W_1/3)O₃ (PFW) and their solid solutions. Low temperature neutron diffraction (ND) studies were carried out on polycrystalline samples in the temperature range of 2K to 300K to understand the structural and magnetic properties. We studied the crystal structure, electric and magnetic properties of (1-x) Pb(Fe_1/2Nb_1/2)O₃ – x Pb(Fe_2/3W_1/3)O₃ (PFN_1-x – PFW_x ) (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) solid solutions. Raman spectroscopy corroborates the changes in structural symmetry from monoclinic (Cm) to cubic (Pm-3m) on varying from x = 0.0 to x = 1.0. The coexistence of both monoclinic and cubic phases was observed for compounds with x = 0.2 to 0.8. Magnetic measurements shows that, the magnetic phase transition from paramagnetic to antiferromagnetic (AFM) was observed at or above RT for x = 0.6 and above. The temperature dependent magnetization (M-T) confirms the augmentation of Néel temperature (T_N) from 155 K to 350 K on increasing x. From the neutron diffraction, magnetic and dielectric measurements corroborates spin lattice and magnetoelectric coupling