Optical Study of α-Fe₂O₃ under Ultrahigh Pressure

Abstract

An optical measurement was made for α-Fe₂O₃ under ultrahigh pressure generated by a diamond cell. Low-energy shifts of the absorptions due to ⁶A_1g→⁴T_1g and ⁶A_1g→⁴T_2g transitions in 3d electrons in Fe ion were observed with increasing pressure up to 300 kbar. The increase of the crystal-field splitting was indicated from the data. A new absorption observed at higher pressure is supposed to be ascribed to the high spin-low spin transition.