It is harder to get strong magnets to “change phase,” because the same properties that make them strong also make their magnetic state more stable and resistant to change.

What “change phase” means here

In a typical physics or materials context, “change phase” for a magnet usually means one of two things:

  • A magnetic phase transition (for example, going from ferromagnetic to paramagnetic when heated past the Curie temperature).
  • A domain reconfiguration or reversal (flipping or erasing the magnetization under an external field or heat).

In both senses, strong permanent magnets are deliberately designed to resist such changes.

Why strong magnets are harder to change

Several material properties are tuned to make high‑performance magnets “stubborn”:

  • High coercivity : Strong rare‑earth magnets (like NdFeB) have high coercivity, meaning a large opposing field is needed to demagnetize or flip them.
  • Engineered microstructure : Defects and grain boundaries are used as “pinning sites” that lock domain walls in place so magnetic domains cannot easily move to a new configuration.
  • Thermal robustness : Additions like dysprosium in NdFeB magnets help them keep magnetization at higher temperatures, preventing an easy phase change to a disordered state until you approach the Curie temperature.

Because of these factors, you generally need:

  1. Very strong external fields to flip or significantly alter their magnetization.
  2. High temperatures near or above the Curie point to drive them into a different magnetic phase.

Both are technically demanding and energy‑intensive compared to weaker, low‑coercivity magnets.

Putting it simply

  • Weak magnets: domains can be rearranged or erased with modest fields or moderate heating.
  • Strong magnets: domains are locked in by design, so “changing phase” (either flipping them or driving a true magnetic phase transition) requires extreme fields, high temperatures, or both, making it much harder.

TL;DR: Yes, for strong magnets, getting them to “change phase” is harder, precisely because their high coercivity and engineered microstructure are meant to prevent their magnetic state from changing easily.

Information gathered from public forums or data available on the internet and portrayed here.