Magnetic Noise Analysis of TMR Heads

Abstract

We studied what effect exchange bias had on magnetic noise under high-temperature or low-aspect-ratio conditions. We found that a steep increase in magnetic noise started at around 150 ˚C with a low exchange bias (Jk ~ 0.4 erg/cm 2), and attributed this to the decrease in exchange bias. We measured the dependence of magnetic noise with a high exchange bias (Jk ~ 1.0 erg/cm 2) on temperature and found that magnetic noise was reduced under high-temperature conditions (~ 250 ˚C). We also found that magnetic noise could be diminished at room temperature even for a TMR head with a low aspect ratio (~ 0.5). This indicates that the pinned layer instability increased by reducing the head size was improved with a high exchange bias.

On the growth of Zn1–xMnxO thin films by plasma‐assisted MBE

“…In that case, scanning electron microscopy (SEM) images showed a strong influence of the Mn content on the surface morphology, which remained rough. So far, 2D growth was only reported for growth on ZnO substrates, but the films were very thin (100 nm) [7]. Here we report on the growth of Zn x Mn 1-x O thin films grown by plasma-assisted MBE.…”

Read Performance Reliability in TMR Head

“…It was examined changing into Material B. The particle diameter distribution of Material B was smaller than the one of Material A, and the blocking temperature was also higher than the one of Material A [14]- [16]. The sample heads were proved with Material B.…”

Read-head Conditions for Obtaining Areal Recording Density of 5.8 Tbit/in.2 on a Bit-Patterned Medium

“…Head noise (namely, electronic noise and thermal magnetic-fluctuation noise), however, becomes large as TWR is decreased, because electrical resistance of the read head increases and volume of the magnetic layer of the MR head decreases. [24][25][26] Besides, medium noise of a BPM is expected to be low because of low transition noise. Accordingly, head noise might be the key factor in obtaining the optimum conditions for designing an MR head.…”