The major hysteresis loop is the magnetic moment of a sample as the applied field is lowered from positive saturation to negative saturation and raised back to positive saturation. While providing a useful global characterization, the major hysteresis loop provides only incomplete information: materials with similar major loops can have very different hysteresis behavior under a more detailed analysis.

One well known way to probe the hysteresis at a more detailed level than the major loop is to examine the magnetization curves obtained by reversing the field before negative saturation is reached, that is, with First Order Reversal Curves (FORCs). As an extension of this idea, one can systematically measure a family of FORCs obtained with a set of equally spaced reversal fields running from positive to negative saturation. The result is a set of data which fills the interior of the major hysteresis loop.

We are working on algorithms to analyze experimental data on a variety of materials (spin glasses, magnetic nanopillars, and single domain particulate magnetic media). At the same time we are doing simulations of hysteresis in related models.

Relevant Publications:

[117.] ``Reversal-Field Memory in Magnetic Hysteresis}, H.G. Katzgraber, F. Pazmandi, C.R. Pike, K. Liu, R.T. Scalettar, K.L. Verosub, and G.T. Zimanyi, Phys. Rev. Lett. 89, 257202 (2003).