Critical behavior, magnetic phase diagram, and magnetocaloric effect in the square-net ferromagnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>NdMn</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi

The square-net ferromagnet ${\mathrm{NdMn}}_{2}{\mathrm{Ge}}_{2}$ has attracted significant attention owing to its zero-field skyrmionic bubbles at room temperature and the associated intriguing topological transport phenomena. Compared with the other members of the $R{\mathrm{Mn}}_{2}{\mathrm{Ge}}_{2}$ family ($R$ = rare-earth elements), this compound exhibits a notably more complex and diverse magnetic structure. In this work, we present a systematic investigation of the magnetic properties of ${\mathrm{NdMn}}_{2}{\mathrm{Ge}}_{2}$. The magnetism predominantly arises from the Mn sublattice across a broad temperature range, with Nd moments becoming significant only at lower temperatures. With increasing external magnetic field applied along the $c$ axis, the ferromagnetic transition temperature ${T}_{\mathrm{c}}$ shifts to higher temperatures, whereas the spin reorientation temperature ${T}_{\mathrm{SR}}$ decreases. Based on these observations, we construct a detailed magnetic phase diagram and interpret the field-induced evolution of the topological magnetic states from an energetic standpoint. Critical exponents extracted from isothermal magnetization curves reveal that the magnetic exchange interaction decays as $J(r)\ensuremath{\sim}{r}^{\ensuremath{-}4.59}$, placing it between short-range and long-range interaction regimes. This intermediate range suggests the coexistence of both interaction types, which may underpin the formation of skyrmionic bubbles in ${\mathrm{NdMn}}_{2}{\mathrm{Ge}}_{2}$. Furthermore, ${\mathrm{NdMn}}_{2}{\mathrm{Ge}}_{2}$ exhibits a maximum magnetic entropy change of $4.16\phantom{\rule{0.16em}{0ex}}\mathrm{J}\phantom{\rule{0.16em}{0ex}}{\mathrm{kg}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$ and a relative cooling power of $218\phantom{\rule{0.16em}{0ex}}\mathrm{J}\phantom{\rule{0.16em}{0ex}}{\mathrm{kg}}^{\ensuremath{-}1}$ at 70 kOe near room temperature. Our results provide a deeper understanding of the magnetic interactions in ${\mathrm{NdMn}}_{2}{\mathrm{Ge}}_{2}$ and shed light on the relationship between its complex magnetic behavior and emergent topological spin textures.