Gamma ferric oxide thin film media with a thickness of 0.190.27 µm were prepared by a reactive RF sputtering. Signal output loss with increasing temperature at high recording density was studies. Heating a medium-head system to 55 results in a 16% loss of signal output at 790 bpm (D-6 dB) of recording density for a medium having a 0.19 µm thickness; a 40% loss of signal output for a conventional-coated medium having a 0.7 µm thickness at 400 bpm (D-6dB), accompanying a decrease of a saturation write current value, IW(k-1) (an optimum write current). Increments of medium thickness and write current enhanced the thermal signal output loss. An over-saturated recording in the write process was suggested to cause the thermal signal output loss, especially for the thicker media. From the perspective of thermal stability of signal output at high recording density, sputtered γ-Fe2O3 thin film media are advantageous because of their thinness and small write current dependence of signal output.

Our compact switching converter using a thin-film microtransformer mono-lithically integrated with rectifier diodes represents the first step in developing a monolithic micro-switching converter that can be integrated with semiconductor devices and magnetic components. This converter is a single-ended forward converter with resonant reset and operates successfully at 15 MHz. The maximum output power is 0.5 W.