The route from fundamental science to technological innovation San Sebastian, November 27, 2017 The route from fundamental science to technological innovation (and the wonders of doing research) A few examples of routes from science to innovations in the Technologies of Information and Communication

the route from fundamental research First example: the route from fundamental research on electrical conduction in magnetic metals to the “big data” stored today on hard disks (and the birth of spin electronics) Second example: from quantum physics to low power computers and telephones

GMR sensor (magnetic multilayer) GMR hard disc drive (GMR = Giant Magnetoresistance) I GMR sensor (magnetic multilayer) Mag. Cu

Opposite magnetizations: GMR hard disc drive (GMR = Giant Magnetoresistance) I GMR sensor (magnetic multilayer) Mag. Cu Opposite magnetizations: large resistance

Parallel magnetizations: GMR hard disc drive (GMR = Giant Magnetoresistance) I GMR sensor (magnetic multilayer) Mag. Cu Parallel magnetizations: small resistance

Spin dependent conduction in ferromagnetic metals South pole North pole Spin up electron Spin down electron Electron  I spin charge Ferromagnetic material (Iron, etc)

Spin dependent conduction in ferromagnetic metals South pole North pole Spin up electron Spin down electron Electron  I spin charge   0.3   20 Ti V Cr Mn Fe Co Ni   =  /  ,  ( cm) 10 20 Ferromagnetic material (Iron, etc)

Spin dependent conduction in ferromagnetic metals South pole North pole Spin up electron Spin down electron Electron  I with Co imp. X X X X spin charge   0.3   20 Ti V Cr Mn Fe Co Ni   =  /  ,  ( cm) 10 20 Ferromagnetic material (Iron, etc)

Spin dependent conduction in ferromagnetic metals South pole North pole Spin up electron Electron with Cr imp.  I spin X X X X charge Spin down electron   0.3   20 Ti V Cr Mn Fe Co Ni   =  /  ,  ( cm) 10 20 Ferromagnetic material (Iron, etc)

Concept of the giant magnetoresistance (GMR)  I X X X X

Concept of the giant magnetoresistance (GMR) Electrons strongly slowed down in both channels: large resist.  I X X X X with Co and Cr imp. X X X X Cu layer 2 magnetic layers with antiparallel magnetizations (AP)  large resistance

Concept of the giant magnetoresistance (GMR) Electrons strongly slowed down in both channels: large resist. Short circuit by electrons in spin up channel: small resist.  I  I XXXXXXX X X X X with Co and Cr imp. with Co and Fe imp. X X X X Cu layer Cu layer Polarizer/Analyzer analogy 2 magnetic layers with antiparallel magnetizations (AP)  large resistance 2 magnetic layers with parallel magnetizations (P)  small resistance

Concept of the giant magnetoresistance (GMR) Electrons strongly slowed down in both channels: large resist. Short circuit by electrons in spin up channel: small resist.  I  I XXXXXXX X X X X with Co and Cr imp. with Co and Fe imp. X X X X Cu layer Cu layer Polarizer/Analyzer analogy Current Perpendicular to Plane Plane-GMR V=RI Current in Plane-GMR

Molecular Beam Epitaxy (growth of metallic multilayers)

(Orsay, 1988, Fe/Cr multilayers, Jülich, 1989, Fe/Cr/Fe trilayers) Giant Magnetoresistance (GMR) (Orsay, 1988, Fe/Cr multilayers, Jülich, 1989, Fe/Cr/Fe trilayers) Jülich Orsay Resistance ratio ~ + 80% Magnetic field (kGauss) Magnetic field (kGauss)

before GMR (< 1997) : 1 Gbit/in2 , today with GMR : ~ 1000 Gbit/in2 Magnetic multilayers, magnetic tunnel junctions in the read heads of hard disks of today and perspective for tomorrow I GMR sensor, introduced in 1997 before GMR (< 1997) : 1 Gbit/in2 , today with GMR : ~ 1000 Gbit/in2 Mag. Mag. Cu

Extension de la technologie disque dur à l’électronique nomade 100 GB hard disc (Toshiba), iPod Classic: 160 G

Giant Magnetoresistance (1988) Pure physics: spin and conduction Nanotechnologies Giant Magnetoresistance (1988) Applications: hard disks, sensors medical technologies Development of spintronics (= electronics exploiting the spin)

Giant Magnetoresistance (1988) Pure physics: spin and conduction Nanotechnologies Giant Magnetoresistance (1988) Applications: hard disks, sensors medical technologies Development of spintronics (= electronics exploiting the spin) 2d example of route between science and innovation: from quantum tunneling to M-RAM

Hard disk and random access memory in computers Random Access Memory (RAM) Massive memory but low speed (ms) High speed (nanosecond range) but « volatile » (electrical power needed to maintain memory alive)

After GMR, TMR (Tunnel magnetoresistance) of tunnel junctions current Electron « tunneling » through an insulationg « barrier » (Al2O3) High resistance Low resistance RAntiparalelP > RParallel M-RAM Non-volatile RAM:no energy needed to keep memory alive (low consumption)

Today: STT-RAM (magnetic tunnel junction+ writing by Spin Transfer Torque) Memory cell = magnetic tunnel junction and reading by tunnel magnetoresistance Purely electronic writing by a spin polarized current (Spin Tranfer Torque mechanism) + High resistance Low resistance STT-RAM = low power RAM reducing energy comsumption in computers and telephones Next year (2018) in your phone In a couple of years as embedded RAMs in the microprocessors of computers

Skyrmions: spin nano-balls and new track for ICTechnologies New routes of today Skyrmions: spin nano-balls and new track for ICTechnologies Diameter 4 nm

Skyrmions: spin nano-balls and new track for ICTechnologies New routes of today Skyrmions: spin nano-balls and new track for ICTechnologies Diameter 4 nm Read write

New routes of today Solid state nanocomponents to mimic neurones and synapses in neuro-inspired computers

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