What term is used for the H field value needed to reduce remanence to zero?

The term "coercive force" refers specifically to the H field value required to reduce remanence to zero in a magnetic material. Remanence is the residual magnetic field that remains in a material after an external magnetic field has been removed. The coercive force is a measure of the material's resistance to changes in magnetization. Essentially, it quantifies the strength of the reverse magnetic field needed to demagnetize the material completely.

In practice, a higher coercive force indicates that the material is more difficult to demagnetize, which directly relates to the efficiency and application of such materials in various technologies. The other terms do not accurately describe this specific relationship: magnetizing force pertains to the external field that magnetizes the material, back emf relates to the electromotive force induced in a circuit due to a change in magnetic flux, and the overlap value lacks relevance to the concepts of magnetic remanence and coercivity.