Magnetic order and dynamical properties of the spin-frustrated magnet Dy2−xYbxTi2O7

The magnetic order and dynamical properties of spin-frustrated magnet Dy2−xYbxTi2O7 single crystals have been studied by dc and ac susceptibility measurements. It is found that the substitution of the Dy3+ by the Yb3+ in Dy2Ti2O7 relaxes ferromagnetic coupling. In low Yb3+ doping samples, a spin freezing peak at Tf (Tf<3 K) and a single-ion effect peak Ts associated with Dy3+ are observed. With increasing Yb3+ doping, a new peak marked by T⁎ associated with Yb3+ appears. We suggest that T⁎ originates from the thermally activated spin fluctuations of Yb3+. It is also found that the relaxation process for Ts becomes both thermally activated and quantum tunneled in x≥1.0 samples. The low-temperature dynamical behaviors of Dy2−xYbxTi2O7 are dominated by the Dy-Yb spin interactions and the altered crystalline electric field. Moreover, crystal field-phonon coupling may contribute to the spin dynamic properties.