LOW-TEMPERATURE SCALING REGIME OF RANDOM FERROMAGNETIC-ANTIFERROMAGNETIC SPIN CHAINS

Using the continuous time quantum Monte Carlo loop algorithm, we calcu late the temperature dependence of the uniform susceptibility, and the specific heat of a spin-1/2 chain with random antiferromagnetic and f erromagnetic couplings, down to very low temperatures. Our data show a consistent scaling behavior in both quantities and strongly support t he conjecture drawn from the approximative real-space renormalization group treatment. A statistical analysis scheme is developed which will be useful for the search of scaling behavior in numerical and experim ental data of random spin chains.