Composition-structure–physical property relationship and nonlinear optical properties of multiferroic hexagonal ErMn1−xCrxO3 nanoparticles

Abstract

Nanocrystalline hexagonal ErMn_1−xCr_xO₃ (0 ≤ x ≥ 0.15) samples have been synthesized by a citrate assisted sol–gel method to study their structural and physical properties. X-ray diffraction studies show that ErMn_1−xCr_xO₃ samples crystallize in the hexagonal phase when the doping concentration is low, while they crystallize into mixed orthorhombic and hexagonal phases at high doping concentrations. The photopyroelectric (PPE) technique is used to determine the thermal parameters of ErMn_1−xCr_xO₃ nanoparticles. Thermal studies indicate that phonon transport through ErMn_1−xCr_xO₃ nanocrystallites reduces as a function of Cr concentration. Temperature dependent magnetic studies show that Cr-doped ErMnO₃ have charge ordered canted (C) type antiferromagnetism (AFM) with a spin-glass transition at low temperature. The striving ferromagnetic (FM) and AFM states are expected to be responsible for the spin-glass type behaviour in Cr doped ErMnO₃. Strong nonlinear optical absorption has been found when the samples are irradiated by laser pulses. The optical limiting response studied against Cr doping shows that nonlinearity varies with dopant concentration.