Tunable magnetization in nanoscale LuFeO3: Role of morphology, ortho-hexa phase ratio and local structure

TL;DR

This study investigates how the phase composition, morphology, and local structure of nanoscale LuFeO3 influence its magnetic properties, revealing tunable magnetization and spin reorientation behavior linked to phase ratio and aspect ratio.

Contribution

It demonstrates the role of phase coexistence, morphology, and local electronic structure in tuning the magnetic behavior of nanoscale LuFeO3, providing insights into structure-property relationships.

Findings

Nanofibers exhibit higher ferromagnetic moments than nanoparticles.

Spin reorientation temperature varies with phase ratio and morphology.

Local structure influences magnetic anisotropy and orbital interactions.

Abstract

We have observed enhancement and shift in the spin reorientation transition temperature as a consequence of coexistence of orthorhombic and hexagonal phases and higher aspect ratio in nanoscale LuFeO3. Nanoparticles and nanofibers of LuFeO3 are considered for this work. Nanoparticles have 75 % orthorhombic phase and 25 % hexagonal phase, while nanofibers have 23% orthorhombic phase and 77%-hexagonal phase. Larger aspect ratio in case of nanofibers is seen to help strain-stabilize the hexagonal phase in the material. Magnetic measurements show significant difference in the magnetic behavior and spin reorientation temperature; 183K for the nanoparticle case and 150K for the case of nanofibers. Moreover, the ferromagnetic moment is two order of magnitude higher for nanofibers than that of nanoparticles, In hexagonal phase, frustration of triangular lattice, works against the long range ordering while magnetic anisotropy works in favor of the long range ordering, which contributes towards the enhanced and anomalous magnetic behavior in case of fibers. X -ray absorption near edge spectroscopy (XANES) at the Fe K-edge has been used to probe the symmetry driven dynamics of Fe 3d- 4p orbitals. It established that due to noncentrocymmetry of the Fe atom, the nanofibers have decreased 3d-4p orbital mixing and reduced crystal field splitting energy, which are also contributing factor for the enhanced magnetic behaviour.