This is the first time that a Spanish physicist has received credit in this country as the discoverer of a new physical phenomenon: the mesoscopic tunnelling of magnetization in molecular magnets (Physical Review Letters, 1996). This scientific breakthrough has now made its way into textbooks on magnetism.
It explains how the magnetic poles of small magnets, formed by millions of atoms, at very low temperatures, can change orientation due to the tunnel effect and without any energy expenditure. Now, the journal Nature has recognized this discovery as a historic milestone in the science of spin (the property of elementary particles to rotate around their axis in relation to their magnetic field).
Milestones in Spin also records the contributions of great figures in the world of physics, such as Nobel Prize winners Albert Einstein (1921); Paul A. M. Dirac (1933); Otto Stern (1943); Felix Bloch and E. M. Purcell (1952), Douglas Osheroff, Robert Richardson and David Lee (1996); Frank Wilczek, David Gross and David Politzer (2004), and Albert Fert and Peter Grünberg (2007).
The uncertainty principle governs the world of quantum physics: it is impossible to know the position and the momentum of an object at the same time. This is a property of quantum objects and does not depend on the ability to make an exact measurement. This uncertainty, at macroscopic scale, cannot be detected experimentally, and this has generated intense scientific debate in the frontiers of quantum physics and in the mesoscopic world. For the researchers, the tunnel effect is an unexpected consequence of quantum mechanics, and the magnets of mesoscopic size are the best systems for detecting quantum tunnelling phenomena.
The collection Milestones in Spin highlights 23 historic events in the study of spin, from the discovery of the first physical phenomenon in this field (the Zeeman effect, 1896) until the present day. Milestone 22, entitled «Mesoscopic tunneling of magnetization» is the quantum tunnel effect in magnetic poles, a phenomenon discovered by Javier Tejada, J. R. Friedman, M. Sarachik and Ron Ziolo and described in the article «Macroscopic measurement of resonant magnetization tunneling in high-spin molecules» (Physical Review Letters, 1996).
In this study, the scientists showed that the reorientation of the magnetic poles of mesoscopic sized magnets occurs due to quantum tunnelling, a curious property of the quantum world according to which an elementary particle can disappear and reappear outside the space in which it is confined.
In accordance with the theories of the physicist Eugene Chudnovsky on the tunnel effect, Tejada and his co-workers study the magnetism of mesoscopic magnets, and have discovered new fundamental laws of quantum phenomena in magnetism: the first experimental evidence of the tunnel effect of magnetization (1992), the resonant spin tunnelling (1996), quantum spin coherence (1999) and quantum magnetic deflagration (2005). Science, Nature, and Physics Today are some of the international journals that reported the new physical effect, discovered in 1996 by the research team at the UB and in the United States.
In the area of spin physics, the article «Field tuning of thermally activated magnetic quantum tunnelling in Mn12-Ac molecules», was the second to report evidence of the tunnel effect using an independent technique, published in the journal Europhysics Letters (1996), by the researchers Javier Tejada, Joan Manel Hernàndez and X. X. Zhang of the Department of Fundamental Physics at the UB, in conjunction with F. Luis and J. Bartolomé of the Materials Science Institute of Aragon and Ron Ziolo of the Xerox Corporation in New York.
The expectations raised by resonant spin tunnelling in the field of applied and basic physics open up new frontiers for the study of new macroscopic quantum phenomena and the testing of theories.
Winner of the Principe de Viana Prize for Culture in 2006, and recipient of an honorary doctorate from the City University of New York in 1996, Javier Tejada is a renowned expert in the field of magnetism and in the study of quantum effects in magnetism and superconductivity using microwaves and acoustic waves as high frequency. Professor of the Department of Fundamental Physics, he is the director of the UBX and the Magnetism Group at the UB, and is a member of the Spanish Royal Society of Physics, the Catalan Society of Physics, the New York Academy of Sciences and the American Physical Society.
Javier Tejada is the author of more than 280 scientific studies in leading journals such as Science, Physical Review Letters, Physical Review B, Europhysics Letters, Applied Physics Letters and Nature Materials. Tejada, who holds fifteen international patents in cooperation with firms and institutions, has been admitted as a Fellow of the American Physical Society (2000), and has received the Narcis Monturiol Medal from the Catalan government (1994), the International Award of the Xerox Foundation (1998) and the Catalan government distinction for the Promotion of University Research (2001).
Rosa Martínez | alfa
OU-led team discovers rare, newborn tri-star system using ALMA
27.10.2016 | University of Oklahoma
First results of NSTX-U research operations
26.10.2016 | DOE/Princeton Plasma Physics Laboratory
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences