Effect of Y³⁺ Doping on Microstructure and Magnetic Transition of CuCrO₂ Ceramics

Ceramic samples of CuCr_1-xY_xO₂ (x = 0-0.02) were synthesized via the high temperature solid-state reaction method, and the influence of Y³⁺ doping on their microstructure and antiferromagnetic phase transitions was systematically investigated. Y³⁺ doping increased the unit cell volume from 130.928 ų for x = 0 to 131.147 ų for x = 0.0200, and the average grain size decreased from 3.38 μm for x = 0 to 4.27 μm for x = 0.0200. The Cr and Y elements maintained +3 valence, while the Cu element had +1 valence. All samples showed obvious paramagnetism when the temperature was higher than 140 K. When the temperature continued to decrease, the lattice expansion changed the bond length and bond angle of the Cr-O-Cr bond, resulting in a change in the superexchange interaction, and the magnetic susceptibility increased significantly, gradually showing antiferromagnetism. The T_N of the undoped sample was about 46 K, the T_N of the doped sample with x = 0.0175 was about 21 K, and the T_N of other doped samples was about 30 K. This result indicates that Y³⁺ doping enhanced the antiferromagnetism of the sample but also weakened its antiferromagnetic stability.