Variation of the lattice and spin dynamics in Bi_{1- x}Dy_xFeO₃ nanoparticles

Infrared and Raman-scattering spectroscopies were employed to explore the lattice and spin dynamics of Bi_1-xDy_xFeO ₃ nanoparticles. With increasing substitution of Bi by Dy in the range of 0.00 ≤ x ≤ 0.40, we observe (1) evidence for an increase of local lattice distortion of the FeO₆ octahedra, and significant changes of phonon parameters in the x = 0.15 sample, corresponding to the structural transformation from rhombohedral to orthorhombic, (2) the chemically substituted enhanced dielectric constant of 43.4 in the x = 0.20 sample, (3) the development of two-magnon excitations in Dy substituted samples, which sensitively gauges the modification of magnetic structures from a cycloidal spin to a homogeneous magnetized state, and (4) Dy substitution disrupts the lattice-spin interactions at high temperatures. These findings extend our understanding of tailoring the structural and magnetic properties of chemically substituted multiferroic nanoparticles and advance the technologically important development of these materials.