Method to calculate performance of a magnetic element comprising a reference bilayer including a ferromagnetic reference layer having a reference magnetization and an antiferromagnetic layer pining the reference magnetization by exchange-bias, the antiferromagnetic layer comprising a metallic polycrystalline material having a grain volume distribution; the method comprising: measuring an exchange-bias field (H ex ) of the.antiferromagnetic layer at selected exposure temperatures (Ts), under selected in-plane exposure magnetic fields (H) applied to the reference bilayer , during an exposure time (τ S ); characterised in that the method is further comprising : fitting a grain volume distribution function to the measured exchange-bias fields (H ex ) to determine at least one distribution parameter characterizing the volume distribution of the grains and at least one magnetic parameter characterizing the magnetic properties of the antiferromagnetic layer ; calculating a reference angle (θ FM ) corresponding to an in-plane variation in the direction of the reference magnetization , as a function of a direction of the exposure magnetic field (H); calculating the exchange bias field (H ex ) for any value of the in-plane exposure magnetic field (H), exposure temperature (T S ) and exposure time (τ S ), using the calculated reference angle (θ FM ) and determined said at least one distribution and magnetic parameters in the grain volume distribution function. measuring an exchange-bias field (H ex ) of the.antiferromagnetic layer at selected exposure temperatures (Ts), under selected in-plane exposure magnetic fields (H) applied to the reference bilayer , during an exposure time (τ S ); characterised in that the method is further comprising : fitting a grain volume distribution function to the measured exchange-bias fields (H ex ) to determine at least one distribution parameter characterizing the volume distribution of the grains and at least one magnetic parameter characterizing the magnetic properties of the antiferromagnetic layer ; calculating a reference angle (θ FM ) corresponding to an in-plane variation in the direction of the reference magnetization , as a function of a direction of the exposure magnetic field (H); calculating the exchange bias field (H ex ) for any value of the in-plane exposure magnetic field (H), exposure temperature (T S ) and exposure time (τ S ), using the calculated reference angle (θ FM ) and determined said at least one distribution and magnetic parameters in the grain volume distribution function. fitting a grain volume distribution function to the measured exchange-bias fields (H ex ) to determine at least one distribution parameter characterizing the volume distribution of the grains and at least one magnetic parameter characterizing the magnetic properties of the antiferromagnetic layer ; calculating a reference angle (θ FM ) corresponding to an in-plane variation in the direction of the reference magnetization , as a function of a direction of the exposure magnetic field (H); calculating the exchange bias field (H ex ) for any value of the in-plane exposure magnetic field (H), exposure temperature (T S ) and exposure time (τ S ), using the calculated reference angle (θ FM ) and determined said at least one distribution and magnetic parameters in the grain volume distribution function. <EOS>