In this paper, we study three specific aspects of entanglement in small spin clusters. We first study the effect of inhomogeneous exchange coupling strengths on the entanglement properties of the S=(1)/(2) antiferromagnetic linear chain tetramer compound NaCuAsO4. The entanglement gap temperature T-E is found to have a nonmonotonic dependence on the value of alpha, the exchange coupling inhomogeneity parameter. We next determine the variation of T-E as a function of S for a spin dimer, a trimer, and a tetrahedron. The temperature T-E is found to increase as a function of S but the scaled entanglement gap temperature t(E) goes to zero as S becomes large. Last, we study a spin-1 dimer compound to illustrate the quantum complementarity relation. We show that in the experimentally realizable parameter region, magnetization and entanglement plateaus appear simultaneously at low temperatures as a function of the magnetic field. Also, the sharp increase in one quantity as a function of the magnetic field is accompanied by a sharp decrease in the other so that the quantum complementarity relation is not violated.
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