Magnetic and Magnetoelectric properties of NdCrTiO_5 revealed by systematically rare-earth doping

We have systematically synthesized polycrystalline samples of Nd_(0.9)A_(0.1)CrTiO_5 (A = Pr, Nd, Gd, Dy, Er, Tm, and Yb), and have investigated their crystal structure, polarization and magnetic susceptibility. The polarization values of doped samples are suppressed comparing to pure NdCrTiO_5 sample, which indicates that the polarization is highly dependence with the magnetic moments of doping ions. The T_N of Cr - Cr in Nd_(0.9)A_(0.1)CrTiO_5 are dominated by both the suppression effect caused by doped magnetic moment increment and the enhancement effect caused by c axis contracting. We conclude that the magnetic moments in the rare-earth Nd sites play an important role in the magnetoelectric effect in NdCrTiO_5 family. The substitution effect discussion here can help us well understand the intrinsic mechanism and provide a possible guidance in exploring new magnetoelectric coupling systems.