Manufacture And Faraday Magneto-Optical Effect Of Highly Transparent Novel Holmium Aluminum Garnet Ceramics

A novel transparent magneto-optical holmium aluminum garnet (HoAG) ceramic with a high in-line transmittance of similar to 80.3 % at 589 nm (similar to 97.0 % of the theoretical transmittance of HoAG single crystal) and a maximal infrared cut-off at similar to 6.5 mu m was successfully fabricated by vacuum sintering at 1650 degrees C. The facile co-precipitation strategy was employed to yield the precipitation precursor with hollow structures upon calcination into the sphere-like HoAG particle with a narrow particle distribution. Silica sintering aid creates point defect of Ho3+ vacancies to promote the HoAG densification rate during sintering by Si4+ substitution for Al3+ in tetrahedrally coordinated 24 (d) sites. The magneto-optical HoAG ceramic has Verdet constants of similar to-154 rad/(T.m) at 635 nm and similar to-36 rad/(T.m) at 1064 nm, which are higher than or similar to that of the commercial TGG single crystal. The thermal conductivity of the transparent HoAG ceramic was determined to be similar to 10.5 W/(m K) at room temperature. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.