Barkhausen-type noise in the resistance of antiferromagnetic Cr thin films

Abstract

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 $M \rightarrow Ψ_0$ and $H \rightarrow T$, where $Ψ_0$ 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.

5 pages, 3 figures. To be published in Europhysics Letters