Longitudinal bias stack for a current-perpendicular-to-plane (cpp) read sensor

A method of fabricating a read head, comprising:

• forming a lower ferromagnetic shield;
• depositing a CPP read sensor on the lower ferromagnetic shield;
• forming a front edge and a back edge on the CPP read sensor
• forming first and second sides of the CPP read sensor in two side regions;
• depositing an insulation layer on the first and second sides of the CPP read sensor and on a portion of the lower ferromagnetic shield;
• depositing a longitudinal bias layer formed of a hard-magnetic Fe—Pt film on the insulation layer;
• and
• forming an upper ferromagnetic shield.

A read head comprising:

• a current-perpendicular-to-plane (CPP) read sensor sandwiched between lower and upper ferromagnetic shields, the CPP read sensor having first and second sides;
• an insulation layer on each of the first and second sides of the CPP read sensor and on a portion of the lower ferromagnetic shield;
• and
• a longitudinal bias stack comprising
• a seed layer on the insulation layer;
• a longitudinal bias layer comprising Fe—Pt on the seed layer;
• and
• a cap layer on the longitudinal bias layer.

A method of fabricating a read head, comprising:

• forming a lower ferromagnetic shield;
• depositing a read sensor on the lower ferromagnetic shield;
• forming front and back edges of the CPP read sensor;
• forming first and second sides of the CPP read sensor in two side regions;
• depositing an insulation layer on the first and second sides of the CPP read sensor and on a portion of the lower ferromagnetic shield;
• depositing a seed layer formed of a nonmagnetic, polycrystalline Ru film on the insulation layer;
• depositing a longitudinal bias layer formed of a hard-magnetic Fe—Pt film on the seed layer;
• depositing a cap layer formed of a nonmagnetic Pt, Rh or Ru film on the longitudinal bias layer;
• and
• forming an upper ferromagnetic shield.

A read head, comprising:

• a current-perpendicular-to-plane (CPP) read sensor sandwiched between lower and upper ferromagnetic shields, the CPP read sensor having first and second sides;
• an insulation layer on each of the first and second sides of the CPP read sensor and on a portion of the lower ferromagnetic shield;
• and
• a longitudinal bias stack comprising
• an electrically insulating seed layer on the insulation layer;
• a longitudinal bias layer on the electrically insulating seed layer;
• and
• a cap layer on the longitudinal bias layer.

A method of fabricating a read head, comprising:

• forming a lower ferromagnetic shield;
• depositing a CPP read sensor on the lower ferromagnetic shield;
• forming front and back edges of the CPP read sensor;
• forming first and second sides of the CPP read sensor in two side regions;
• depositing an insulation layer on the first and second sides of the CPP read sensor and on a portion of the lower ferromagnetic shield;
• depositing an electrically insulating seed layer formed of a nonmagnetic, polycrystalline MgO film on the insulation layer;
• depositing a longitudinal bias layer formed of a hard-magnetic Fe—Pt film on the electrically insulating seed layer;
• depositing a cap layer formed of a nonmagnetic Pt, Rh or Ru film on the longitudinal bias layer;
• and
• forming an upper ferromagnetic shield.

A read head, comprising:

• a current-perpendicular-to-plan (CPP) read sensor sandwiched between lower and upper ferromagnetic shields, the CPP read sensor having first and second sides;
• an insulation layer on each of the first and second sides of the CPP read sensor and on a portion of the lower ferromagnetic shield;
• and
• a longitudinal bias stack comprising
• an electrically insulating seed layer on the insulation layer;
• an electrically conducting seed layer on the electrically insulating seed layer;
• a longitudinal bias layer on the electrically conducting seed layer;
• and
• a cap layer on the longitudinal bias layer.

A method of fabricating a read head, comprising:

• forming a lower ferromagnetic shield;
• depositing a CPP read sensor on the lower ferromagnetic shield;
• forming front and back edges of the CPP read sensor;
• forming first and second sides of the CPP read sensor in two side regions;
• depositing an electrical insulation layer on the first and second sides of the CPP read sensor and on a portion of the lower ferromagnetic shield;
• depositing an electrically insulating seed layer formed of a nonmagnetic, polycrystalline MgO film on the insulation layer;
• depositing an electrically conducting seed layer formed of a nonmagnetic, polycrystalline Ru film on the insulating seed layer;
• depositing a longitudinal bias layer formed of a hard-magnetic Fe—Pt film on the conducting seed layer;
• depositing a cap layer formed of a nonmagnetic Pt, Rh or Ru film on the longitudinal bias layer;
• and
• forming an upper ferromagnetic shield.