  We present an experimental study of the changes generated on the electrical
resistance $R(T)$ of epitaxial Cr thin films by the transformation of quantized
spin density wave domains as the temperature is changed. A characteristic
resistance noise appears only within the same temperature region where a
cooling-warming cycle in $R(T)$ displays hysteretic behavior. We propose an
analysis based on an analogy with the Barkhausen noise seen in ferromagnets.
There fluctuations in the magnetization $M(H)$ occur when the magnetic field
$H$ is swept. By mapping $M \rightarrow \Psi_0$ and $H \rightarrow T$, where
$\Psi_0$ corresponds to the order parameter of the spin density wave, we
generalize the Preisach model in terms of a random distribution of {\it
resistive hysterons} to explain our results. These hysterons are related to
distributions of quantized spin density wave domains with different sizes,
local energies and number of nodes.
