Performance of focused ion beam trimmed yoke-type magnetoresistive heads for magnetic microscopy
- Resource Type
- Periodical
- Authors
- Phillips, G.N.; Eisenberg, M.; Draaisma, E.A.; Abelmann, L.; Lodder, J.C.
- Source
- IEEE Transactions on Magnetics IEEE Trans. Magn. Magnetics, IEEE Transactions on. 38(5):3528-3535 Sep, 2002
- Subject
- Fields, Waves and Electromagnetics
Ion beams
Magnetoresistance
Voltage
Focusing
Magnetic heads
Sensor phenomena and characterization
Transistors
Magnetic force microscopy
Milling
Surface reconstruction
- Language
- ISSN
- 0018-9464
1941-0069
Thin-film yoke-type magnetoresistive (MR) tape heads with eight channels have been used for scanning magnetoresistance microscopy. The NiFe read flux guides of the channels have been trimmed down from 12 /spl mu/m to widths varying between 5 /spl mu/m and 100 nm by focused ion-beam milling with Ga/sup +/ ions. The tape-bearing surface of the milled regions has been reconstructed in situ by the local deposition of Pt. Tracks with a minimum bit length of 1 /spl mu/m have been written on Co-Ni-O metal evaporated tape and Co-/spl gamma/-Fe/sub 2/O/sub 3/ particulate tape with trimmed and untrimmed write channels and have been successfully imaged with all the trimmed read channels. A linear decrease in readback voltage across the MR sensor is observed for channels possessing flux guides trimmed down to 2 /spl mu/m, in agreement with finite-element modeling of the trimmed heads. The severe attenuation in readback voltage observed for flux guides trimmed below 2 /spl mu/m is attributed to a combination of micromagnetic effects. Additionally, damage to the NiFe from Ga/sup +/ ion implantation may make a minor contribution to the loss in sensor performance. A 65% drop in readback voltage is observed for a channel possessing a flux guide that was trimmed by 98.3% to 200 nm.