Magnetic properties of YFeO3 nanocrystals obtained by different soft-chemical methods

Abstract

In recent years materials based on nanocrystalline YFeO3 draw considerable research interest as the basis of innovative magnetic and magneto-optical devices. However, the size and the morphology of the nanocrystals are well-known to have a drastic influence on its functional properties. In present work, the effect of size and morphological features on magnetic properties of YFeO3 nanocrystals is investigated. Yttrium orthoferrite nanocrystals were synthesized via four soft-chemical routes—glycine-nitrate synthesis (GNS), thermal treatment of GNS products, hydrothermal and thermal treatments of co-precipitated hydroxides. Obtained samples were characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM) and vibrational magnetometry (VM). It was shown that synthesized compositions correspond to single-phase nanocrystals of orthorhombic YFeO3 with different morphology (isometric, plate-like, rod-shaped) and average crystallite sizes ranging from 29 ± 3 to 58 ± 6 nm depending on synthesis route. Basic magnetic characteristics of its nanocrystals—residual magnetization (M res ) and coercivity (H coerc )—also show strong dependence on YFeO3 synthesis route, average crystallite size and its morphology and vary in the ranges 70–273 emu/mol and 1.8–21.0 kOe correspondingly. It was found that nanocrystals with isometric morphology obtained by different synthesis routes demonstrate simultaneous increase of residual magnetization and decrease of coercivity with growth of crystallite size. However, it was also found that as morphology becomes nonisometric (plate-like and rod-shaped) these trends are not observed anymore and magnetic behavior of YFeO3 is defined by interactions of weak-ferromagnetic and antiferromagnetic orderings in nanocrystals along its anisotropic directions.