| 초록 |
We synthesized a series of slightly Er substituted yttrium iron garnet (Y3-xErxFe5O12) at different Er concentrations (x = 0, 0.01, 0.05, 0.10 and 0.20) using a solid state reaction and investigated their structural, magnetic and optical properties as a function of Er concentration. We found that Er atoms replace Y atoms rather than Fe atom in YIG based on the analysis of XAS and XMCD measurements. The optical properties exhibited certain decreases in reflectance in the 1500-1600 nm wavelength range, due to the presence of Er3+. Even though Er atom has a large magnetic moment (7/2 mB) due to unpaired 4f electrons, the magnetic properties of YIG were rarely modified by Er substitution in most temperature range. However, as the magnetic moments decreased below 20 K, the magnetic properties such as magnetic moments, residual magnetism and coercive force, were decreased as increasing Er atom, which could be originated from antiferromagnetic ordering of Er atoms against Fe ions. Our studies show that above 20 K the magnetic properties of YIG are retained even with Er substitution, which could be applicable for YIG-based magneto-optical devices in the mid-infrared regime. |
