Tunneling magnetoresistive (TMR) read head with reduced gap thickness

• Main Authors: Sangmun Oh, Susumu Okamura, Zheng Gao
• Format: Patent
• Language: English
• Published: 10.08.2016
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS

A tunneling magnetoresistive (TMR) read head 200 has a read gap with a reduced thickness. A multilayer seed layer 225 includes a first ferromagnetic seed layer 225a on a lower shield S1, a ferromagnetic NiFe 225b alloy on the first seed layer, and may have a third seed layer 225c of Ru or Pt on the NiFe seed layer. The first and NiFe seed layers are magnetically part of the lower shield, thereby effectively reducing the read gap thickness. A free layer/capping layer structure includes a multilayer ferromagnetic free layer 210 and an Hf capping layer 212a on the free layer. The free layer includes a CoB or CoFeB upper layer 210b in contact with the Hf capping layer prior to annealing and a Fe or CoFe sub layer. When the sensor is annealed Hf can diffuse into the B-containing upper layer, forming an interface layer 210c. The Hf-containing interface layer possesses negative magnetostriction, so the free layer is not required to contain NiFe.