Tunneling magnetoresistive (TMR) device with magnesium oxide tunneling barrier layer and free layer having insertion layer

A tunneling magnetoresistive (TMR) read head comprising:

• a first shield layer of magnetically permeable material;
• a reference ferromagnetic layer on the first shield layer and having an in-plane magnetization direction substantially prevented from rotation in the presence of an external magnetic field;
• an electrically insulating tunneling barrier layer consisting essentially of MgO on and in contact with the reference layer;
• a free ferromagnetic multilayer on the tunneling barrier layer and having an in-plane magnetization direction oriented substantially orthogonal to the magnetization direction of the reference layer in the absence of an external magnetic field, the free ferromagnetic multilayer comprising a first ferromagnetic layer on the tunneling barrier layer, a nickel-iron (NiFe) alloy ferromagnetic compensation layer having an Fe content equal to or less than 15 atomic percent, and a NiFe alloy ferromagnetic insertion layer having an Fe content equal to or greater than 40 atomic percent between said first ferromagnetic layer and said ferromagnetic compensation layer;
• a capping layer on the free ferromagnetic multilayer;
• and
• a second shield layer of magnetically permeable material on the capping layer.

A tunneling magnetoresistive (TMR) read head comprising:

• a first shield layer of magnetically permeable material;
• a reference ferromagnetic layer on the first shield layer and having an in-plane magnetization direction substantially prevented from rotation in the presence of an external magnetic field;
• an electrically insulating tunneling barrier layer consisting essentially of MgO on and in contact with the reference layer;
• a free ferromagnetic multilayer on the tunneling barrier layer and having an in-plane magnetization direction oriented substantially orthogonal to the magnetization direction of the reference layer in the absence of an external magnetic field, the free ferromagnetic multilayer comprising:
• a CoFe alloy nanolayer having an Fe content equal to or greater than 20 atomic percent and equal to or less than 80 atomic percent on the MgO barrier layer;
• a CoFeB alloy ferromagnetic layer on the CoFe alloy nanolayer;
• an amorphous separation layer selected from Ta, Zr, Hf, a CoFeBTa alloy and a CoHf alloy on the CoFeB alloy layer;
• a NiFe alloy ferromagnetic compensation layer having an Fe content equal to or less than 15 atomic percent;
• and
• a NiFe alloy ferromagnetic insertion layer having an Fe content equal to or greater than 40 atomic percent and less than or equal to 55 atomic percent between said separation layer and said NiFe alloy compensation layer;
• a capping layer on the free ferromagnetic multilayer;
• and
• a second shield layer of magnetically permeable material on the capping layer.