Experimental Evidence for Ising Spin-Glass Transition in the YbCoGaO4 Single Crystal

Magnetic measurements (ac and dc susceptibilities and magnetization) on YbCoGaO4 single crystal as a function of frequency and temperature are presented. The studied system behaves like a three-dimensional Ising-like spin glass. A cusp is seen only in the longitudinal susceptibility, whereas a paramagnetic behavior is observed in the transverse susceptibility. Typical spin glass features are observed in the frequency and temperature dependence of the ac susceptibility. Dynamical scaling is performed and critical exponents are deduced and compared to those obtained for Ising and Heisenberg systems. The origin of the Ising anisotropy of Yb3+ and Co2+ions is briefly discussed.