  We examine the magnetic properties of the quasi 2D ferrimagnetic single
crystal Mn3Si2Te6 (MST) through critical phenomena and magnetic entropy
analysis in the easy axis (H || ab) as a function of proton irradiance.
Employing a modified asymptotic analysis method, we find that upon proton
irradiation the critical exponents do not fall into any particular universality
class but lie close to mean field critical exponents ({\gamma} = 1, \b{eta} =
0.5). The presence of long-range interactions can be safely assumed for the
pristine and irradiated cases of MST examined in this work. Further analysis on
the effective spatial dimensionality reveal that MST remains at d = 3 under
proton irradiation transitioning from an n = 1 spin dimensionality to n = 2 and
n=3 for 1 x 10^15 and 5 x 10^15 H+/cm^2, indicating an XY interaction and a
Heisenberg interaction, respectively. The pair (spin-spin) correlation function
reveals an increase in magnetic correlations at the proton irradiance of 5 x
10^15 H+/cm^2. In conjunction, the maximum change in magnetic entropy obtained
from isothermal magnetization at 3 T is the largest for 5 x 10^15 H+/cm^2 with
a value of 2.45 J/kgK at T = 73.66 K, in comparison to 1.60 J/kgK for pristine
MST at T = 73 K. Magnetic entropy derived from zero-field heat capacity does
not show large deviations across the proton irradiated samples. This suggests
that the antiferromagnetic coupling between the Mn sites is stable even after
proton irradiation. Such result implies that magnetization is enhanced through
a strengthening of the super-exchange interaction between Mn atoms mediated
through Te rather than a weakening of the AFM component. Overall, our study
finds that the magnetic interactions are manipulated the greatest when MST is
irradiated at 5 x 10^15 H+/cm^2.
