Mozaic Technology Innovation

Gen 7 Spintronic Reader

The Industry's Smallest, Most Sensitive Magnetic Field Sensor

Discerning minute changes in magnetization, our Gen 7 spintronic reader ensures data is read accurately and swiftly at ultra-high areal densities.


It starts with a quantum mechanical phenomenon.

It's called tunneling magnetoresistance. This happens when the electrical resistance of a magnetic tunnel junction (MTJ) changes depending on the relative orientation of magnetic layers separated by an insulating barrier. Leveraging this phenomenon allows for high-resolution magnetic readback, crucial for accurately reading smaller, densely packed bits.


The read head includes a complex stack of magnetic and non-magnetic layers.

It includes the free layer (FL) sensitive to external magnetic fields from recorded data, the reference layer (RL) with stable magnetic orientation, and the synthetic antiferromagnet to prevent the RL's magnetic orientation from influencing the FL.


These layers convert magnetic signals from recorded bits into electrical signals for data retrieval.


The stack’s design enhances sensitivity and signal-to-noise ratio.

Using specialized magnetic sensors, the reader detects changes in the magnetic field as the read head passes over recorded bits. This ensures precise reading from the intended track while minimizing crosstalk from adjacent tracks, enabling precise readback from the superlattice platinum-alloy media.


The stack is constructed through multi-chamber deposition.

This manufacturing process remains under continuous vacuum to avoid contamination, with precise control over each layer's thickness. Materials and layer thicknesses provide thermal stability. The magnesium oxide barrier layer in the tunnel junction undergoes controlled oxidation for optimal sensitivity.

Seagate's Gen 7 spintronic reader marks a significant advancement in reading data from the densely packed tracks enabled by Mozaic 3+™.