Abstract
In this study we calculate the specific heat CVI for NH4AlF4 due to the nearest-neighbor interactions between the NH+ 4 tetrahedra using an Ising model superimposed on an Einstein and/or Debye model. The specific heat CVI calculated using a power-law formula is in good agreement with the observed CP for the NH4AlF4 system. This is an indication that NH4AlF4 undergoes a weak first-order or a nearly second-order phase transition as predicted by our model.
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Yurtseven, H., Yanik, A. Order-disorder phase transition in NH4AlF4 . JPE 23, 502–505 (2002). https://doi.org/10.1361/105497102770331190
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DOI: https://doi.org/10.1361/105497102770331190