code: def H_mag(self, T):
          
  
          tau = T / self.Tc_mag
  
          if tau <= 1.0:
              h = (-self._A_mag/tau +
                   self._B_mag*(tau**3/2 + tau**9/15 + tau**15/40))/self._D_mag
          else:
              h = -(tau**-5/2 + tau**-15/21 + tau**-25/60)/self._D_mag
  
          return R*T*math.log(self.beta0_mag + 1)*h
docs: Calculate the phase's magnetic contribution to enthalpy at the
          specified temperature.
  
          :param T: [K] temperature
  
          :returns: [J/mol] The magnetic enthalpy of the compound phase.
  
          Dinsdale, A. T. (1991). SGTE data for pure elements. Calphad, 15(4),
          317–425. http://doi.org/10.1016/0364-5916(91)90030-N