The delta M curves predicted by the vector Preisach model are analyzed and proved to always be negative. A mean interaction field parallel to the magnetization is added to the model so as to reproduce the positive delta M curve of barium ferrite particulate media. By using this model in self consistent field computation, the typical overwrite behavior of barium ferrite has been reproduced. Calculated dc-erasure has been found to be more efficient than ac-erasure, which is consistent with experimental results.