  Superparamagnetism (SPM) is an attractive material property often appearing
in nanoscaled single domain (SD) configurations. However, not all SD particles
are superparamagnetic, which depends on a few parameters including material
type, temperature, measurement time and magneto crystalline anisotropy. The
non-linear magnetisation response of magnetic particles can be interpreted by
classical Langevin approach but its applicability is limited to pure SD-SPM
behaviour. The classical Langevin equation lacks parameters to account for
possible remanence and coercivity in SD regime, resultantly, the SD-nonSPM
possibility is left untreated. To solve this issue, we propose a new model by
including SD coercivity parameters in classical Langevin equations. The new
model 1) combines steady or time varying magnetisation dynamics and temperature
or particle size dependent coercivity and 2) helps to calculate coercivity
compensated magnetisations and susceptibilities directly. The model covers full
spectrum of SD diameters and defines the switching between superparamagnetic
and non-superparamagnetic states more precisely.
