Al-doping-induced magnetocapacitance in the multiferroic CuCrS₂

In this paper, magnetic and dielectric properties of the quasi-two-dimensional triangular-lattice system CuCrS₂ and its B-site-diluted analogs CuAl_1-xCr_xS₂ (x=0.01 and x=0.02) are investigated. Antiferromagnetic phase transition is observed at about 38.5 K by magnetization measurement without shift induced by a small amount of dopping Al. Magnetodielectric effect is found near T_N in each of the three compounds. The dielectric constant decreases and the magnetocapacitance increases with the increase of substitution of nonmagnetic Al³⁺ ions for the magnetic Cr³⁺ ions. The negative magnetocapacitive effect reaches ～13% for CuAl_0.02Cr_0.98S₂.