The 200th Special MMU seminar
Conductive oxide for spacer layer of CPP-GMR sensors
Dr. Tomoya Nakatani
HGST, a Western Digital company, San Jose, California, USA
Date: November 28th (Fri), 2014
Time: 10:30 - 11:30
Place: 8th floor medium seminar room (Room 811-812), Sengen
Read sensor using magnetoresistance (MR) device is a key component for hard disk drives.
As the recording bit size becomes smaller, the resistance-area product (RA) of the sensor film is required to be smaller.
However, the suitable RA value for the read sensor for >1 Tbit/in2 of recording density is expected to be ~0.1 Ω・μm2,
which cannot be satisfied by either tunnel magnetoresistance (TMR) sensors (> 0.3 Ω・μm2) or all-metal current-perpendicular-to-plane
giant magnetoresistance (CPP-GMR) sensors (~0.05 Ω・μm2). Therefore, the material technology to fill the gap of RA between
TMR and CPP-GMR is required. In this work, we applied In-Zn-O (IZO) conductive oxide to spacer layer of CPP-GMR. We observed
larger MR ratios in CoFe/IZO/CoFe spin-valves than those with metal (Cu and Ag) spacers, and the RA ranged from 0.1 to 0.3 Ω・μm2
depending on the IZO spacer thickness. The large interface resistance at CoFe/IZO may be the origin of the relatively large CPP-GMR.
Therefore, studying conductive oxides or semiconductors for spacer layer of CPP-GMR devices is thought to be a frontier of both
fundamental interest and practical importance.
This result was presented at 59th MMM Conference. (T. Nakatani, and J. R. Childress, CG-05, Nov. 5, 2014)