Albert Fert

Albert Fert
Fert in 2008
Albert Fert
Born	7 3, 1938
Birthplace	Carcassonne, France
Nationality	French
Occupation	Physicist
Employer	Université Paris-Saclay, Unité Mixte de Physique CNRS/Thales, Michigan State University
Known for	Giant magnetoresistance, spintronics, skyrmions
Awards	CNRS Gold Medal (2003), Wolf Prize in Physics (2006), Nobel Prize in Physics (2007)

Albert Fert (born 7 March 1938) is a French physicist whose discovery of giant magnetoresistance (GMR) fundamentally transformed data storage technology and opened an entirely new field of condensed matter physics known as spintronics. Born in the southern French city of Carcassonne, Fert pursued studies at two of France's most distinguished academic institutions — the École normale supérieure in Paris and the University of Paris — before embarking on a research career that would bridge fundamental physics and industrial application. His landmark 1988 observation that the electrical resistance of certain multilayered metallic structures changed dramatically in the presence of a magnetic field provided the physical basis for a new generation of read heads in hard disk drives, enabling the rapid expansion of digital storage capacity into the gigabyte era and beyond. For this achievement, Fert was awarded the 2007 Nobel Prize in Physics, shared with the German physicist Peter Grünberg, who had independently made a similar discovery. An emeritus professor at Université Paris-Saclay and scientific director of a joint laboratory between the Centre national de la recherche scientifique (CNRS) and Thales Group, Fert has also served as an adjunct professor at Michigan State University. His subsequent research interests have extended from GMR into the physics of magnetic skyrmions and, more recently, orbitronics.

Early Life

Albert Fert was born on 7 March 1938 in Carcassonne, a historic city in the Aude department of southern France. Details of Fert's family background and upbringing are not extensively documented in public sources, though his trajectory from provincial France to the elite academic corridors of Paris traces a path through the French educational system's rigorous selection processes. Growing up in the post-war period, Fert came of age during an era of significant investment in French scientific research and higher education, as the country rebuilt its intellectual infrastructure following the Second World War.

Carcassonne, known primarily for its medieval fortified city, was not a major center of scientific activity, and Fert's eventual move to Paris for advanced study marked the beginning of his immersion in the world of theoretical and experimental physics. His early interest in the physical sciences led him to pursue admission to one of France's grandes écoles, the highly competitive institutions that have traditionally served as training grounds for the country's scientific and intellectual elite.

Education

Fert received his higher education at two of France's foremost academic institutions. He studied at the École normale supérieure (ENS) in Paris, one of the most selective and prestigious grandes écoles in the French educational system, known for producing a disproportionate number of France's leading scientists, mathematicians, and philosophers. He subsequently continued his academic training at the University of Paris, where he pursued doctoral research under the supervision of Ian Campbell. His doctoral work focused on the physics of electrical transport in ferromagnetic metals, a subject area that would remain central to his research throughout his career. The combination of the rigorous theoretical grounding provided by the ENS and the experimental research environment of the University of Paris equipped Fert with the tools and perspective necessary for his later groundbreaking work on magnetoresistance in metallic multilayers.

Career

Early Research and the Physics of Spin-Dependent Transport

Following the completion of his doctoral studies, Fert established himself as a researcher in condensed matter physics, with a particular focus on the behavior of electrons in magnetic materials. His early career was centered at the Laboratoire de Physique des Solides at what is now the Université Paris-Saclay (formerly the Université Paris-Sud) in Orsay, a suburb of Paris that had become one of France's principal hubs for physics research.

Fert's research during the 1970s and 1980s examined the mechanisms by which the spin of electrons — an intrinsic quantum mechanical property — influenced their transport through metallic systems containing magnetic elements. This work built on earlier theoretical and experimental studies of the anomalous behavior of electrical resistance in ferromagnetic metals and alloys, a problem that had occupied physicists since the mid-twentieth century. Fert and Ian Campbell developed models of spin-dependent scattering in ferromagnetic metals that would prove foundational for the later understanding of giant magnetoresistance.

The concept that electrons with different spin orientations ("spin-up" and "spin-down" relative to the magnetization direction of a material) experience different scattering rates as they travel through a ferromagnet was central to Fert's early contributions. This spin-dependent scattering means that the electrical conductivity of a ferromagnetic metal can be described, to a useful approximation, as the sum of two parallel conduction channels — one for each spin orientation. This "two-current model" became a key framework for understanding the transport properties of magnetic metals and alloys, and it provided the intellectual foundation upon which the discovery of giant magnetoresistance was built.

Discovery of Giant Magnetoresistance

The discovery for which Fert is best known occurred in 1988, when his research group at the Université Paris-Sud observed an unusually large change in the electrical resistance of thin-film structures composed of alternating layers of iron (Fe) and chromium (Cr). When the magnetization directions of adjacent iron layers were aligned by an applied magnetic field, the electrical resistance of the multilayer structure dropped substantially — by as much as 50% at low temperatures. This effect was far larger than any previously known magnetoresistance phenomenon in metals, and Fert and his collaborators named it "giant magnetoresistance" (GMR).

The physical mechanism underlying GMR is rooted in the spin-dependent scattering that Fert had studied throughout his career. In the Fe/Cr multilayer system, the chromium spacer layers mediate an antiferromagnetic coupling between adjacent iron layers, causing their magnetizations to align in opposite directions in the absence of an external magnetic field. In this antiparallel configuration, electrons of both spin orientations are strongly scattered as they pass from one iron layer to the next, resulting in high electrical resistance. When an external magnetic field is applied with sufficient strength to overcome the antiferromagnetic coupling and align all the iron layer magnetizations in the same direction (the parallel configuration), electrons of one spin orientation pass through with relatively little scattering, creating a low-resistance channel and reducing the overall resistance of the structure dramatically.

The 1988 paper reporting this discovery, published in Physical Review Letters with Fert's doctoral student M. N. Baibich as the lead author, became one of the most cited papers in condensed matter physics. A follow-up paper in 1989 provided further characterization of the effect in Fe/Cr multilayers.

Independently and nearly simultaneously, the German physicist Peter Grünberg at the Forschungszentrum Jülich made a similar observation in Fe/Cr/Fe trilayer structures. The independent and convergent nature of these two discoveries underscored the robustness and significance of the GMR effect.

Impact on Data Storage Technology

The practical significance of giant magnetoresistance became apparent within less than a decade of its discovery. The technology industry recognized that GMR-based sensors could detect much smaller magnetic fields than the anisotropic magnetoresistance (AMR) sensors then in use as read heads in hard disk drives. By the mid-1990s, IBM and other manufacturers had developed GMR-based read heads that dramatically increased the areal density of magnetic data storage — the amount of data that could be stored per unit area of a hard disk platter.

This technological revolution enabled the transition from hard drives storing megabytes of data to those storing gigabytes, and eventually terabytes. The explosive growth in digital storage capacity that characterized the late 1990s and 2000s — facilitating the rise of the internet, digital media, cloud computing, and big data — was directly enabled, in significant part, by the application of the GMR effect that Fert and Grünberg had discovered in the laboratory. As the Nobel Prize committee noted, the discovery brought about "a breakthrough in gigabyte hard disks."

Spintronics and Subsequent Research

The discovery of GMR is widely credited with launching the field of spintronics (spin electronics), a branch of condensed matter physics and engineering that exploits the spin degree of freedom of electrons in addition to, or instead of, their charge. While conventional electronics relies on the flow of electrical charge, spintronics seeks to manipulate and detect the spin states of electrons to store, process, and transmit information. GMR was the first practical spintronic effect, and its commercial success demonstrated that spin-based phenomena could be harnessed for technological applications at industrial scale.

Following the GMR discovery, Fert continued to make contributions to the rapidly expanding field of spintronics. His research group investigated a range of spin-dependent transport phenomena, including spin injection, spin accumulation, and spin-orbit coupling effects in various material systems. His position as scientific director of the Unité Mixte de Physique, a joint laboratory operated by the CNRS and the Thales Group, placed him at an interface between fundamental research and industrial application — a position that facilitated the transfer of spintronic concepts from the laboratory to practical devices.

Skyrmions and Topological Spin Structures

In the years following the Nobel Prize, Fert turned significant attention to the study of magnetic skyrmions — nanoscale, topologically protected spin configurations in which the magnetic moments of atoms form a swirling, vortex-like pattern. Skyrmions had been predicted theoretically and observed experimentally in certain magnetic materials, and their unusual topological properties — which make them robust against small perturbations — suggested potential applications as ultra-compact information carriers in future data storage and logic devices.

A 2013 review article in Nature Nanotechnology, co-authored by Fert, outlined the prospects for using skyrmions as mobile bits of information in "racetrack memory" architectures, in which data is stored in the form of skyrmions moving along nanoscale magnetic tracks. This concept offered the potential for data storage devices with densities and speeds exceeding those achievable with conventional magnetic recording or even spin-transfer torque magnetic random access memory (STT-MRAM).

Fert's work in this area also involved the study of chiral spin structures at interfaces, the role of the Dzyaloshinskii-Moriya interaction in stabilizing skyrmions in thin films and multilayers, and the dynamics of skyrmion motion under applied currents.

Orbitronics

More recently, Fert and his collaborators have contributed to the emerging field of orbitronics, which is based on the use of orbital angular momentum currents — as distinct from spin currents — as information carriers. A 2024 study published in Nature Communications involving researchers associated with Fert's group investigated light-induced orbital currents in nickel using terahertz emission experiments, demonstrating that orbital currents can be generated from the conversion of charge currents and detected through their coupling to spin currents. A related 2024 study demonstrated efficient orbitronic terahertz emission based on CoPt alloy, quantifying the transport of orbital currents in a new material system. This line of research represents a further extension of the conceptual framework underlying spintronics, exploring whether orbital degrees of freedom can provide complementary or superior functionality for information processing.

Affiliations and Collaborative Work

Throughout his career, Fert has maintained affiliations with multiple institutions. He has been an emeritus professor at the Université Paris-Saclay in Orsay and has served as scientific director of the Unité Mixte de Physique CNRS/Thales. He has also held an adjunct professorship at Michigan State University.

In 2020, Fert joined a collaborative effort with the University of the Basque Country (UPV/EHU), expressing interest in exploring new properties of quantum matter through collaborative research.

Recognition

Albert Fert has received numerous awards and honors in recognition of his contributions to physics and technology.

In 2003, he was awarded the CNRS Gold Medal, the highest distinction conferred by the French Centre national de la recherche scientifique, recognizing the totality of his contributions to condensed matter physics and, in particular, his discovery of giant magnetoresistance and his foundational role in establishing the field of spintronics.

In 2006, Fert received the Wolf Prize in Physics, one of the most prestigious international awards in the field, shared with Peter Grünberg for their discovery of the GMR effect.

In 2007, Fert was awarded the Japan Prize, a major international award recognizing original and outstanding achievements in science and technology.

The culmination of these recognitions came with the 2007 Nobel Prize in Physics, which Fert shared with Peter Grünberg "for the discovery of Giant Magnetoresistance." In his speech at the Nobel Banquet held in Stockholm City Hall on 10 December 2007, Fert addressed the assembled dignitaries and guests.

Fert's work has also been recognized through his election to various scientific academies and his receipt of other national and international honors, reflecting the broad impact of his research across both fundamental physics and applied technology.

Legacy

Albert Fert's scientific legacy rests on several interconnected contributions. His most consequential achievement — the discovery of giant magnetoresistance — has had a dual impact, both as a fundamental advance in the understanding of spin-dependent electron transport in nanoscale structures and as the enabling technology for a generation of hard disk drives that powered the digital information revolution of the late twentieth and early twenty-first centuries.

The broader legacy of Fert's work is the establishment and growth of spintronics as a major field of research and technology. The GMR effect demonstrated that the quantum mechanical spin of the electron could be exploited for practical purposes, opening the door to a range of subsequent developments including tunnel magnetoresistance (TMR), spin-transfer torque, spin Hall effects, and spin-orbit torque devices. These phenomena now underpin technologies such as magnetic random access memory (MRAM) and are the subject of active research aimed at developing next-generation computing architectures.

Fert's more recent work on magnetic skyrmions has contributed to the exploration of topologically protected spin textures as potential information carriers, a concept that could lead to storage and logic devices with characteristics fundamentally different from those of current technologies. His engagement with orbitronics represents an extension of the spintronic paradigm into new physical territory, probing whether orbital angular momentum can serve functions analogous to those of spin in information technology.

Through his dual role as a researcher at a national laboratory and a collaborator with the Thales Group, Fert exemplified a model of scientific research in which fundamental discovery and technological application proceed in tandem. His career trajectory — from the two-current model of electrical transport in ferromagnets, through the discovery of GMR, to the exploration of skyrmions and orbital currents — traces the evolution of an entire branch of condensed matter physics over more than five decades.