CEF effects of Ho1−xDyxNi2B2C

We have studied the crystalline electric field (CEF) effect of the Ho1−xDyxNi2B2C system using the anisotropy and the temperature dependence of magnetic susceptibilities with magnetic field H perpendicular or parallel to c  -axis, and estimated the magnetic exchange interaction constant Jex⊥ of rare-earth ions perpendicular to the c  -axis. The crystalline electric field parameter B20, the first Steven parameter and the most dominant term in this system, are determined from the Jex⊥ and anisotropic Weiss temperatures and then show a broad minimum around x≈0.3, where superconducting transition temperature, TC, and Néel temperature, TN, are similar.