where \(T_{\min}\) and \(T_{\max}\) correspond to the minimum and maximum temperatures over which the fit will be defined.
To account for the magnetic field dependence, we allow for the fitting coefficients \(c_i\) in the Chebyshev expansion to vary in value with magnetic field; we calculate the magnetic field dependence of each Chebyshev coefficient \(c_i\left(B\right)\) by fitting \(R\left(T\right)\) data at a series of fixed magnetic fields and expressing the resulting \(c_i\left(B\right)\) coefficients as rational polynomials (Padé approximants) . Specifically, we represent the fractional variation of \(c_i\left(B\right)\) with respect to its zero field value \(c_i\left(0\right)\) as