Elucidation of atomic and magnetic structures of Al3+-doped Li-ferrite (LiFe5O8) compounds

Abstract

Chemical stress for structural deformation in

, denoted as Li60Al40, and

, denoted as Li50Al50, was achieved by introducing

into α-

known as a high-temperature multiferroic. These new solid solution compounds crystallize in the tetragonal space group P4₃2₁2. Their magnetic spin arrangements at 300 K could be determined in the magnetic space group P4₃2₁ ${}^{\prime }{2}^{\prime }$ using high-resolution neutron powder diffraction (HRNPD) data. Within the experimental uncertainty in HRNPD, the magnetic moments of

ions within

in the B-sublattice are arranged along the crystallographic c axis and antiparallel to those of

in the A-sublattice. In comparison to the Fe-rich Li60Al40, the Fe-poor Li50Al50 shows a stronger dilute effect for the higher Li content at the octahedral site Fe1b. The dilute effect is associated with the lowering of both saturation magnetization and $T_C$. On the other hand, Li50Al50 shows large electric dipole moments in the strong distorted

and

polyhedra.