Scaling behavior of the magnetization of Si:B.

We show that the non-linear magnetization of acceptors in insulating Si:B exhibits a universal behavior similar to that found for donors in Si:P, for fields up to 50 kG and temperatures down to 1.25 K. Based on an extension to finite fields of the Bhatt and Lee scaling theory for the s = 1/2 donor system, we show that an equivalent calculation for j = 3/2 correctly predicts the magnetic properties of the acceptor system. This indicates that a model of hierarchically coupled spin pairs with renormalized interactions can provide a quantitative description of the magnetic behavior of acceptors as well as donors.