Manifestation of chemical pressure: Magnetism and magnetostriction in nanoscale RFeO3 (R = Sm, Dy, Ho, and Lu)

Abstract

The effect of ionic radii sizes on magnetostriction is studied in relation to structural and magnetic properties. To explore the effect of the chemical pressure, nanoparticles of rare-earth (RE) orthoferrites, SmFeO3, DyFeO3, HoFeO3, and LuFeO3 are studied using X-ray diffraction, field emission scanning electron microscopy, and Raman spectroscopy. Magnetic and magnetostriction measurements are also performed. In these orthoferrites, the coordination of the RE ion is eightfold, whereas the RE ionic radii are significantly different, which directly influences the structural parameters. The distortion of FeO6 octahedra is observed as a result of changing chemical pressure within the lattice. The different magnitudes of magnetostriction in RE orthoferrites can be attributed to the different degrees of distortion of FeO6 octahedra, R–O dynamics, and spin–orbit interactions in the system. The maximum value of magnetostriction (∼ 19 ppm) and magnetization at 2 K (30.64 emu/g) is demonstrated by HoFeO3. Comparison of structural parameters of the samples to their respective bulk counterparts indicated relative structural distortion in nanoparticles.