Materials Research for Advanced Data Storage

Transcription

1 Materials Research for Advanced Data Storage University of Alabama Center for Materials for Information Technology Fall Review November 18, 2002

2 Center for Materials for Information Technology (MINT) at The University of Alabama A multidisciplinary research program focusing on new materials for advanced data storage. 22 faculty, 10 postdocs, and 40 graduate students from 7 academic programs in science and engineering. Support federal grants (including an NSF Materials Research Science & Engineering Center grant), industry (IBM, Seagate, Quantum, Sony, Fujitsu, Hitachi Maxell, INSIC), and University support.

3 Materials Research for Advanced Data Storage Fundamental Materials Problems in Magnetic Data Storage Storing Writing Reading Flexible Media Storage Molecular Storage Spintronics

4 TEM Images of Self-Assembled [Fe 49 Pt 51 ] 88 Ag 12 Nanoparticle Films ( particles/in 2 ) Before Annealing Annealed at 400 o C for 30 min Contact: J.W. Harrell and Dave Nikles

5 Effect of Various Underlayers on Hc G/Underlayer(t nm)/fe65co35 (50 nm) Contact: Bill Doyle

6 AF(IrMn) CoFe CCP-CPP Spin Valves via Nano-Oxide Layers Cu Cu NOL (SiO 2 ) RA nom ~500m R/R~0.25% R CPP GMR device with current path constricted by nano-oxide layers increase R A MR transfer-curve observed for a CCP- CPP structure with a nominal area of 50µm 2. Contact: Hideo Fujiwara

7 Nanochannels via Nano-Oxide Layers (NOL) AF(IrMn) CoFe Cu Cu NOL (SiO 2 ) CPP GMR device with current path constricted by nano-oxide layers. RA nom ~500m R/R~0.25% R MR transfer-curve observed for a CCP-CPP structure with a nominal area of 50µm 2. Contact: Hideo Fujiwara

8 Particle Ordering In Flexible Media SANS Data Contact: JohnWiest Model Predictions

9 A Molecular Storage System RGD molecule 2-5 nm tip with voltage control + molecular storage layer (protective or adhesive layer) semi-conducting substrate project goal: storage densities (2D) Tb/in 2 Research Team Si Blackstock Greg Szulczewski

10 Contacts: Mankey, Schad, Zangari, Fujiwara Spin Transport in Confined Geometries Insulating layer with nanochannels Pinned layer Ni wires Cu lead Co Free layer 1-10 nm J σ Co Electrodes Nanochannels CPP GMR with Confined Current Paths Nanocontacts Very large magnetoresistance from nanoscale constrictions Cu lead Nanowires Spin transfer effect

11 Ilmenite-Hematite as Magnetic Semiconductors 150 Seebeck Coefficient ( µv/k) p n Composition x T=300K T=400K For 0.1< x < 0.5, I-H is ferrimagnetic and semiconducting. The magnetic properties depend on the degree of order of the cation lattice. Contacts: R. Schad and K. Pandey

12 Half-metallic ferromagnets Calculated electronic structure of CrO 2 - Only known stoichiometric binary oxide that is a conductive ferromagnet at 300 K. S. P. Lewis et al., Phys. Rev. B 55, (1997) - Known to be a half-metal, i.e., 98.4 % spin-polarized at E f. Contact: Greg Szulczewski

13 Half-metallic ferromagnets Proposed device structure metal 50nm CrO 2 (100) 1nm TiO 2 (100) 200nm CrO 2 (100) TiO 2 (100) Contact: Greg Szulczewski