Long saturation zone magnetic write head

In a magnetic recording head having:

• a bottom yoke member having a first relatively wide and planar tip area;
• a top yoke member having a second relatively narrow and planar tip area;
• said first and second planar tip areas being coplanar and defining a generally planar recording gap;
• said generally planar recording gap being adapted to move relative to generally planar magnetic recording media;
• coil means associated with said bottom and top yoke members;
• and
• current energizing means for energizing said coil means with current of a magnitude Iw;
• said current energization of said coil means causing magnetic flux to flow, and to produce a given magnetic flux gap field Bg at said magnetic recording gap, said top yoke member comprising;
• a first yoke portion having a generally large cross-sectional area;
• said first yoke portion being directly associated with said coil means;
• a second yoke portion having a first generally large cross-sectional area connected to said first yoke portion, and having a first generally smaller cross-sectional area that is spaced from said first generally large cross-sectional area;
• said second yoke portion having a cross-sectional area that reduces at a first rate when considered from said first generally large cross-sectional area to said first generally smaller cross-sectional area;
• a third yoke portion having a second generally large cross-sectional area connected to said first generally smaller cross-sectional area;
• and having a second generally smaller cross-sectional area that is spaced from said second generally large cross-sectional area;
• said third yoke portion having a cross-sectional area that reduces at a second rate that is less than said first rate when considered from said second generally large cross-sectional area to said second generally smaller cross-sectional area;
• and
• a throat yoke portion having a generally constant cross-sectional area;
• said throat yoke portion having one end connected to said second generally smaller cross-sectional area, and having an opposite end defining said second relatively narrow and planar tip area;
• said first and second rates of cross-sectional area reduction being selected to cause said third yoke portion to uniformly saturate along its length as a result of said energization of said coil means, to thereby provide said given magnetic flux gap field Bg at said magnetic recording gap.