Investigation of spin-1 Blume-Capel and mixed spin (1/2, 1) Ising models in the framework of thermodynamic geometry

Spin-1 Blume-Capel and mixed spin (1/2, 1) Ising models are studied making use of thermodynamic geometry in the Ruppeiner formalism. Thermal metric tensors are derived and corresponding thermodynamic curvatures or Ricci scalars (R) are computed for the order parameter spaces of both models. These are investigated for various parameter regimes, including the first- and second-order phase transitions. R tends towards plus infinity (R → +∞) while approaching the second-order phase transition and tricritical point. Finite jumps with sign changes connected with first-order phase transitions as well as magnetic and crystal field dependent broad extrema in the Ricci scalar are also found. Finally, geometric phase diagrams including critical topology are presented.