  In this study, I have investigated the magnetic and critical properties of
manganese pyrochlore fluoride NaSrMn$_{2}$F$_{7}$, which exhibits a glass
transition at T$_\text{f}$$=$2.5 (K) due to charge disorder. A DFT+$U$+SOC
framework is used in this paper to derive spin-Hamiltonian terms, including
isotropic and anisotropic exchange interactions. An optimized geometry reveals
a local distortion of the F-Mn-F angle along the $ < $111$ > $ direction
(95.48$^{\circ}$ and 84.51$^{\circ}$), which is considered a weak bond disorder
($\delta J$). In spite of the complex structure of this material, first
principle calculations show that its magnetic properties are only controlled by
the nearest neighbor's Heisenberg exchange interaction, and other interactions
do not affect spin arrangements in the ground state. Thus, this material is
considered a suitable candidate for studying electron correlation in spin
glasses. Using a replica-exchange framework, Monte Carlo simulations indicate
that no phase transition is observed when magnetic susceptibility changes with
temperature. Based on $\delta J$ and the spin Hamiltonian, 2.6 (K) is obtained
as the phase transition temperature.
