Thermal decay study of various magnetization patterns

Summary form only given. To date, most published measurements of the thermal stability of magnetic recordings on thin film media have been of single tone (ST, square wave or all-ones pattern) recordings. An all-ones pattern stores no information and by necessity, information is therefore stored in a magnetization pattern containing many different frequency components. A pattern containing information is not expected to decay as strongly as a single tone written at the frequency of the highest frequency component. A simple superposition of the demagnetizing fields associated with one transition shows that the average demagnetizing field is higher for an ST than for a pseudo-random sequence (PRS) pattern. The decay is accelerated by demagnetizing fields and therefore one expects ST signals to decay more quickly than PRS signals. To mimic application conditions more closely, we have investigated the decay of the components of a 15-tone PRS pattern and compare this with the decay of single tone patterns spanning the frequency range.