TODO can anything interesting and deep be said about "why phase transition happens?" physics.stackexchange.com/questions/29128/what-causes-a-phase-transition on Physics Stack Exchange
This is the most classical type of phase diagram, widely used when considering a substance at a fixed composition.
Composition phase diagrams are phase diagrams that also consider variations in composition of a mixture. The most classic of such diagrams are temperature-composition phase diagrams for binary alloys.
The more familiar transitions we are familiar with like liquid water into solid water happen at constant temperature.
However, other types of phase transitions we are less familiar in our daily lives happen across a continuum of such "state variables", notably:
- superfluidity and its related manifestation, superconductivity
- ferromagnetism
Articles by others on the same topic
A phase transition is a change between equilibrium phases associated with nonanalytic thermodynamic behavior in an appropriate infinite-system limit. Melting, liquid–vapor coexistence and magnetic ordering illustrate different kinds. A phase diagram specifies the control parameters and the boundaries between phases.
At a first-order phase transition, a first derivative of the relevant thermodynamic potential changes discontinuously; thermal examples can have latent heat and phase coexistence. At a continuous phase transition, an order parameter can develop continuously while response functions and a correlation length become singular. Real finite systems show rounded signatures, so measurements usually compare heat capacity, density, structural scattering or an order parameter across a controlled scan. Hysteresis is evidence of delayed conversion or metastability, rather than the definition of an equilibrium transition.
