Superconductivity basics in materials science What is the standard term for the temperature at which certain materials undergo a transition to the superconducting state (zero electrical resistance and Meissner effect)?

Introduction / Context:
The question checks foundational terminology in superconductivity. When a material becomes superconducting, it exhibits zero direct-current electrical resistance and expels magnetic flux (Meissner effect). The specific temperature at which this phase transition occurs is a key material parameter used by engineers and physicists for cryogenic design, magnet systems, and electronics.

Given Data / Assumptions:

• We are discussing conventional usage in solid-state physics and electrical engineering.
• Materials may be type I or type II superconductors.
• The transition occurs upon cooling in zero or small magnetic fields (field effects are ignored here).

Concept / Approach:
The accepted name for this temperature is the transition temperature, commonly denoted Tc. It is the hallmark point of the superconducting transition. Other thermal landmarks—Curie temperature and Néel temperature—refer to magnetic ordering transitions in ferromagnets and antiferromagnets, respectively, and do not imply superconductivity.

Step-by-Step Solution:
Identify the property: onset of superconductivity (zero resistance + Meissner effect).Recall the standard symbol: Tc.Match with vocabulary: the term is 'transition temperature' (or 'critical temperature').

Verification / Alternative check:
Handbooks list Tc for materials such as Hg, Pb, Nb, NbTi, Nb3Sn, and cuprates (YBCO). Datasheets and phase diagrams consistently use 'superconducting transition temperature'.

Why Other Options Are Wrong:

• Curie temperature: temperature where ferromagnets lose spontaneous magnetization.
• Néel temperature: temperature where antiferromagnets lose ordered antiparallel spins.
• Onnes temperature: not a standard technical term; Heike Kamerlingh Onnes discovered superconductivity, but the term is not used for Tc.
• Blocking temperature: used in superparamagnetism for nanoparticle systems.

Common Pitfalls:

• Confusing magnetic ordering temperatures with superconducting transition temperature.
• Believing 'critical temperature' is different; it is synonymous with transition temperature in this context.

Final Answer:
Transition temperature