Evaluation of MP tape packing homogeneity through depth-probing

The particle packing of MP tape media is explored by means of a new measurement technique. Utilizing a narrow gap length record head, the tape is evaluated throughout its thickness with the use of an incremental DC erase measurement. A quantitative analysis of the medium noise spectra at different erase currents allows for the packing fluctuations at different depths into the tape to be proportioned. The technique provides a method for evaluating the interface between the magnetic recording layer and non-magnetic underlayer in dual-layer tape, and measurements indicate that interfacial roughness at the magnetic coating backside in some dual-layer media is a major source of medium noise.