I have three different curves for three different temperatures. The expression I'm trying to fit the data to looks like this: $E_b=E_0(1-\tau/\tau_0)^{\alpha} (1-T/T_m)$. So I'm trying to fit the energy barrier ($E_b$) data to stress and want same $E_0, \tau_0, \alpha, T_m$ fitting parameters for each curves so that with different temperatures the fitting will produce the individual curves. I tried the following with MATLAB: lattice_const_calc.m ( but the fitting is way off). Would appreciate it if someone could help out.
Thanks!