Dr. Joshua M. Pomeroy*, Dr. H. Grube, Dr. A.C. Perrella # #recently deceased (1) (2) (3) Advanced materials synthesis for spin-based electronics (a new process approach to hard drive read heads)

Motivating Objective Electronic device performance can be improved by producing materials with “ideal” properties that are not intrinsic to known materials One strategy is to seek new, “undiscovered” materials with specific properties Alternatively, NIST process constructs combinations of known materials such that the “hybrids” have properties not native to the constituents

Specific Market Opportunity MRS Bulletin 31 p. 375 “Moore’s Law” of Magnetic Recording (hard drives) We want more storage capacity, but physically smaller hard drives Literally EVERY computer sold has a hard drive

Hard drives: Three important pieces 1.Write – Get information onto “paper”OK 2.Retain – “Paper” must last a long timeOK 3.Read – Have to restore the informationChallenges Materials Research Society Bulletin 31 p. 379

Resistance Area product Engineers like resistance to stay the same, even if size (area) changes, therefore, need adjustable RA product Resistance x Area (RA) - resistance property of layered materials For the same layers – ½ area = 2 x Resistance Resistance x Capacitance (RC) speed; large RC = slow ½ A x 2 R = RA A x R = RA

Two “Read” sensors – RA product limitation Low resistance metal based CPP-GMR type sensors (metal/metal/metal layer structures) RA ~ m  m 2 Problem: very small signal! High resistance insulator based MTJ type sensors (metal/insulator/metal layer structures) RA ~ M  m 2 Problem: too slow (RC too big)!

Modified Oxides Magnetic Sensors Industry Need : Continuously variable RA for a single sensor design with useable MR (signal strength). HCIMO  Quality Oxides with variable resistance Ferromagnet Metal Spacer Ferromagnet  All metallic  Low RA product (1-10 mΩ●μm2) GMR RA (Ω  m 2 ) Ferromagnet Insulating Barrier Ferromagnet  Uses insulators  High RA product (10+ Ω●μm 2 ) MTJ

Overview of Method 1.Build the “base” of the electronic device by depositing electrodes and an insulating layer 2.Expose the insulating layer to highly charged ions (Coulomb bombs) – creating small, individual “craters” in the insulator 3.Deposit upper device structure over the irradiated insulator, thereby filling the craters with metal The layer that was initially an insulator becomes a combination of metal and insulator (1) (2) (3) Patent Pending – Application #12/036,729 – licensing opportunities available.

Huge RA product range from one recipe Using conventional strategies, each data point would require the development of a new recipe—a huge expense! All points produced from one recipe

Modified Oxide Read Sensor Performance MR > 20% (good signal) NIST process is compatible with working “read” sensors

Product Development Opportunities Specific market opportunity – NIST process provides variable-RA “read” sensors like those required for high density hard drive sensor packages – requires a “tool” This example also maps to MRAM industry, and other resistance based sensor markets While the ultimate customer is likely a large magnetic storage company, individual process tools are developed and provided by a wide range of smaller companies Patent Application #12/036,729 – licensing opportunities available.