Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with high-resistivity amorphous ferromagnetic layers

A current-perpendicular-to-the-plane magnetoresistive read head for reading magnetically recorded data from tracks on a magnetic recording medium, the head comprising:

• a first shield layer of magnetically permeable material;
• a seed layer on the first shield;
• an antiparallel (AP) pinned structure comprising a first AP-pinned (AP1) ferromagnetic layer on the seed layer and having an in-plane magnetization direction, a second AP-pinned (AP2) ferromagnetic layer having an in-plane magnetization direction substantially antiparallel to the magnetization direction of the AP1 layer, and an AP coupling (APC) layer between and in contact with the AP1 and AP2 layers;
• an electrically conductive nonmagnetic spacer layer on the AP2 layer;
• a free ferromagnetic layer on the spacer layer and having an in-plane magnetization direction oriented substantially orthogonal to the magnetization directions of the AP1 and AP2 layers in the absence of an external magnetic field;
• a capping layer on the free ferromagnetic layer;
• and
• a second shield layer of magnetically permeable material on the capping layer;
• wherein the AP2 layer comprises a multilayer of a first AP2 film, said first AP2 film comprising an amorphous ferromagnetic alloy comprising a nonmagnetic element X, wherein X is selected from the group consisting of B, Tb, Si, Ge, Nb and Mg, and at least one of Co, Ni and Fe;
• and a second AP2 film comprising a crystalline alloy of one or more of Co, Fe and Ni, wherein said second AP2 film is between and in contact with said first AP2 film and the spacer layer.

A current-perpendicular-to-the-plane magnetoresistive read head for reading magnetically recorded data from tracks on a magnetic recording medium, the head comprising:

• a first shield layer of magnetically permeable material;
• a seed layer on the first shield;
• an antiparallel (AP) pinned structure comprising a first AP-pinned (AP1) ferromagnetic layer on the seed layer and having an in-plane magnetization direction, a second AP-pinned (AP2) ferromagnetic layer having an in-plane magnetization direction substantially antiparallel to the magnetization direction of the AP1 layer, and an AP coupling (APC) layer between and in contact with the AP1 and AP2 layers;
• an electrically conductive nonmagnetic spacer layer on the AP2 layer;
• a free ferromagnetic layer on the spacer layer and having an in-plane magnetization direction oriented substantially orthogonal to the magnetization directions of the AP1 and AP2 layers in the absence of an external magnetic field;
• a capping layer on the free ferromagnetic layer;
• and
• a second shield layer of magnetically permeable material on the capping layer;
• wherein the AP2 layer comprises a laminate of two ferromagnetic layers ferromagnetically coupled across a nonmagnetic layer, at least one ferromagnetic layer in the AP2 laminate comprising an amorphous ferromagnetic alloy comprising a nonmagnetic element X, wherein X is selected from the group consisting of B, Tb, Si, Ge, Nb and Mg, and at least one of Co, Ni and Fe.