Seed layer for TMR or CPP-GMR sensor
US8164862B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 2, 2008 |
| Grant date | Apr 24, 2012 |
| Priority date | — |
| Expiry date | Feb 23, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F10/3272
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A composite seed layer that reduces the shield to shield distance in a read head while improving Hex (exchange coupling field) and Hex/Hc (Hc=coercivity) is disclosed and has a SM/A/SM/B configuration in which the SM layers are soft magnetic layers, the A (amorphous) layer is made of at least one of Co, Fe, Ni, and includes one or more amorphous elements, and the B layer is a buffer layer that contacts the AFM (anti-ferromagnetic) layer in the spin valve. The SM/A/SM stack together with the S1 (bottom) shield forms an effective shield such that the buffer layer serves as the effective seed layer while maintaining a blocking temperature of 260° C. in the AFM layer. The lower SM layer may be omitted. Examples of the amorphous layer are CoFeB, CoFeZr, CoFeNb, CoFeHf, CoFeNiZr, CoFeNiHf, and CoFeNiNbZr while the buffer layer may be Cu, Ru, Cr, Al, or NiFeCr.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.