Rotational hysteresis for domain wall motion in the presence of demagnetizing fields

A formula for the rotational hysteresis parameter R
H
is found for the case of domain wall motion (Kondorsky model) in the presence of specimen demagnetizing fields. The particular case studied is thin magnetic films with infinite lateral extent. The result is that specimen demagnetizing reduces values of R
H
. The relation for R
H
is:
R_{H} = \frac{4}{x} \ln(l+x)
where x = 4πM
s
/H
c
. The shape of the rotational torque curves is sketched.