Tunneling magnetoresistive (TMR) device with magnesium oxide tunneling barrier layer and free layer having insertion layer

• Main Authors: Sangmun Oh, Zheng Gao
• Format: Patent
• Language: English
• Published: 02.11.2016
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; INDUCTANCES; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; MAGNETS; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; NANOTECHNOLOGY; PERFORMING OPERATIONS; PHYSICS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; STATIC STORES; TRANSFORMERS; TRANSPORTING

A tunneling magnetoresistance (TMR) or magnetic tunnel junction MTJ device comprising a thin MgO tunneling barrier layer and a free ferromagnetic multilayer which includes a CoFeB first ferromagnetic layer, a face centered cubic (fcc) NiFe compensation layer with negative magnetostriction, and a body centered cubic (bcc) NiFe insertion layer between the CoFeB layer and the fcc NiFe compensation layer. An optional ferromagnetic nanolayer (e.g CoFe) may be located between the MgO barrier layer and the CoFeB layer. An optional amorphous separation layer of, for example Ta, Zr, Hf, CoHf or CoFeBTa, may be located between the CoFeB layer and the bcc NiFe insertion layer. The bcc NiFe insertion layer (including amorphous separation layer) prevents the fcc NiFe compensation layer from adversely affecting the crystalline formation of the MgO and CoFeB layers during annealing. The bcc NiFe insertion layer also increases the TMR and lowers the Gilbert damping constant of the free ferromagnetic multilayer. The fcc NiFe compensation layer may comprise a concentration of 15% or less atomic percent iron (Fe), whilst the bcc NiFe insertion layer may comprise of 40% or more of iron (Fe). The reference layer may form a part of an antiparallel (AP) pinned ferromagnetic structure which comprises an antiferromagnetic layer exchange coupled to a first AP pinned ferromagnetic layer. Further embodiments relate to a Tunneling Magnetoresistive (TMR) read head comprising a further first and second shield layer of magnetically permeable material and a capping layer on the free ferromagnetic multilayer.