Experimental study of the influence of particle size and switching field distribution on video tape output

With recorded wavelengths well under 1 micron the geometric dimensions of the particles start to have significant influence on the output of particulate media. The recorded wavelengths of well under 1 micron being used in video storage approach the length dimensions of standard recording pigments. As a single domain particle cannot support a magnetic transition along its length, the finite length of the particle leads to a reduction in the maximum output signal analogous to the gap loss function and known as length loss. At the same time also the magnetic homogeneity as expressed by (1-S*) becomes increasingly important. The authors experimentally verify the theoretical predictions regarding the influence of the particle parameters by measuring different sets of experimental tapes prepared with appropriate pigment samples