材料期刊网

Three-dimensional (3D) Ising universality in magnets and critical indices at fluid-fluid phase transition

Phase Transitions

Experimental data for critical exponents in some magnetic materials are compared with recent theoretical results on the three-dimensional (3D) Ising model, as derived by one of us (ZDZ) based on two conjectures [Z.D. Zhang, Conjectures on the exact solution of three-dimensional (3D) simple orthorhombic Ising lattices, Phil. Mag. 87 (2007), pp. 5309-5419]. It is found that critical exponents in some bulk magnetic materials indeed form a 3D Ising universality. Our attention is then focused on the critical indices at fluid-fluid phase transition. We suggest to use Zhang's exponent = 3/8 to fit the experimental data over the wider asymptotic region near the critical point of a fluid-fluid phase transition. The 3D Ising universality should exist for critical indices in a certain class of magnets and at fluid-fluid phase transition.

关键词: magnetically ordered materials;fluid-fluid;phase transitions;order-disorder effects;ferromagnetic curie temperature;liquid critical phenomena;x-ray-scattering;critical exponents;critical-point;coexistence;curves;binary-solutions;ionic-solutions;behavior;equation