In this study, the mathematical expression of temperature dependence upper critical magnetic field (Hc2), angle
dependence of upper critical magnetic field (Hc2), and temperature dependence of Ginzburg-Landau (GL)
characteristics were investigated. The parameters were computed by using two band Ginzburg-Landau (GL)
phenomenological model for Ba(Fe1-xNix)2As2 iron based superconductor. Application of very small external
magnetic field at low temperature to nickel doped BaFe2As2 changes to Ba(Fe1-xNix)2As2 iron based superconductor
at a critical temperature of 19.5 K. The phase diagrams of the two upper-critical field and GL characteristics
length were plotted as a function of angle and temperature for Ba(Fe1-xNix)2As2 iron based
superconductor using the experimental values. The phase diagram shows the linear dependence of upper critical
magnetic field parallel and perpendicular ( ) with temperature (T). Correspondingly, the phase diagrams
of the upper critical field (Hc2()) versus the angle () were plotted. The parallel and perpendicular to
the symmetry axis of coherence length (ξGL(T)) and penetration depth (λGL(T)) versus temperature were plotted.
In these plots both parameters are increased with increasing temperature and diverges at the critical temperature
for the superconductor Ba(Fe1-xNix)2As2. This theoretical investigation was found to be in agreement
with the obtained experimental results.