In fitteia consider the following definitions in the appropriate fields in the fitter module:

1. Independent variable: tau

2. Dependent variable: Mz

3. Expression: Mz=Minf\+(M0-Minf)*exp(-tau/T1)

4. fitting parameters: Minf,M0,T1

The "\+" will produce a plot where "Mz" and the contributions "Minf" and "(M0-Minf)*exp(-tau/T1)" will drawn.

In other fitting software substitute "\+" by "+".

In the case of inversion-recovery magnetization decay experiments we might have M0 ≈ -Minf