Editing Disk read-and-write head (section)

=== TMR heads===
In 2004, the first drives to use [[magnetic tunnel effect|tunneling MR]] (''TMR'') heads were introduced by [[Seagate Technology|Seagate]]<ref name=comphist-museum/> allowing 400 GB drives with 3 disk platters. Seagate introduced TMR heads featuring integrated microscopic heater coils to control the shape of the [[transducer]] region of the head during operation. The heater can be activated prior to the start of a write operation to ensure proximity of the write pole to the disk and medium. This improves the written magnetic transitions by ensuring that the head's write field fully [[saturation (magnetic)|saturates]] the magnetic disk medium. The same thermal actuation approach can be used to temporarily decrease the separation between the disk medium and the read sensor during the readback process, thus improving signal strength and resolution. By mid-2006 other manufacturers have begun to use similar approaches in their products.