Magnetic properties of tetragonal Ce1-xLuxB2C2 (≤ x ≤ 0.31) compounds

Specific heat, dc- and ac-magnetic susceptibility and magnetization measurements were performed on rare earth intermetallic compounds Ce1-xLuxB2C2 (0 less than or equal to x less than or equal to 0.31) in order to elucidate the magnetic interaction in CeB2C2. In the process of the substitution of Cc by Lu in CeB2C2, the characteristics of magnetic transition change from a first-order transition to a second-order one. Furthermore, the spinglass phase appears at Lu concentration x = 0.31. We suppose that the ferromagnetic (FM) and antiferromagnetic (AFM) interactions compete and nearly cancel out each other in CeB2C2, and hence that a biquadratic interaction might cause the first-order magnetic transition at T-N. The Lu substitution breaks the competition between AFM and FM interactions and brings forth randomness in interactions acting on each Ce moment. The typical spin-glass behavior of x = 0.31 originates in this random distribution of magnetic interactions.