MIG mini composite head using single crystal Mn-Zn ferrite

Metal-in-gap (MIG) miniature composite heads whose magnetic circuit is composed of single-crystal Mn-Zn ferrite and sputtered Fe-Al-Si film were prepared. Recording and readback characteristics are compared with those of MIG heads using polycrystalline Mn-Zn ferrite. The relationship between timing asymmetry and bit shift is discussed. Results of magnetic-domain observation by SPIN SEM (scanning electron microscopy) are presented. The output voltage of the single-crystal ferrite MIG head showed a 35% higher value than that of ordinary polycrystalline ferrite. This result is due to the higher readback efficiency, arising from higher permeability of the stressed ferrite. Bit shifts of single-crystal MIG heads are small because of their small timing asymmetry and sharp distribution. Timing asymmetry fluctuations are thought to be due to Barkhausen-like domain-wall pinning through readback. This phenomenon is much less significant in single-crystal ferrites; hence, MIG heads are more suitable for high-density recording than polycrystalline ferrite heads