Other topics

At INMA we carry out a great deal of research into the most diverse topics in the field of materials science. Do you know what a molecular magnet is? Or what other things gold is used for? What materials can withstand temperatures of more than 1,600º C? How can we cool using magnets? All these topics and many more can be found below.

Non-natural amino acids to improve the properties of peptides

The last decades have seen an enormous development in the chemistry of peptides – molecules similar to proteins, i.e. built from smaller molecules, i.e. amino acids, but smaller than proteins. Not only with respect to their isolation from natural sources but also their synthesis, structural identification and elucidation of their mode of action. Peptides have therefore been of interest in fields as diverse as chemistry, biochemistry, pharmacology, medicinal chemistry and biotechnology.

The properties of peptides, consisting of chains of amino acids connected together by what is called a peptide bond, depend on the number, type and sequence of the different types of naturally occurring amino acids found in their structure.

Modern organic chemistry has numerous tools at its disposal that allow the preparation of new types of non-natural amino acids. Therefore, one of the most important scientific challenges of recent years is the preparation of new amino acids specially designed to improve the properties and stability of a peptide when these amino acids are incorporated into the peptide structure.

More information: Non-natural amino acids to improve peptide properties

The modern alchemist: chemical behaviour and new applications of gold

Gold, although used and valued since the origins of mankind, has been one of the least known metals until relatively recently. The spectacular development of knowledge of the chemical behaviour of gold since 1970, which has been taking place over the last three decades, is opening up new and, until recently, unsuspected areas of work, highlighting its uniqueness among the elements of the Periodic Table.

The modern alchemist is the one who works with gold to find new applications for this metal or its compounds: A) New synthetic methods, which make possible the preparation and characterisation of a large number of complexes. B) Compounds with luminescent properties. C) Compounds with anti-tumour properties. D) Preparation of polymers containing gold centres that may have application as catalysts.

Further information: The modern alchemist: chemical behaviour and new applications of gold.

High temperature materials

Today’s technological development is demanding higher and higher working temperatures as the performance of any thermal machine improves with increasing temperature and in the aviation industry increasing speed leads to increasing airframe temperatures.

When these working temperatures do not exceed 400°C, we can use today’s steels and light alloys. But we have all observed the high temperatures reached on space shuttles when re-entering the sample (about 1000°C). To protect people and material, slabs of material composed of aluminium borosilicate fibres and silica are used. These materials have to be replaced on each flight. And it will become increasingly necessary to develop materials that can withstand higher temperatures.

Refractory metals such as tungsten, tantalum, titanium or molybdenum exist, but they are very rare and expensive. The solution can be found in the field of ceramics. Today’s technology makes it possible to manufacture parts from a multitude of inorganic compounds, such as silicates, oxides, carbides or nitrides. The main problem with these materials is that they are very fragile.

So what happens if we combine a metal with a ceramic? The addition of ceramic particles to a metal improves its resistance to deformation at high temperatures and the addition of metallic particles to a ceramic increases its toughness and resistance to rupture. This is what is called CERMET, and one example is zirconia-titanium that can work at 1650ºC.

At INMA, we are developing materials for use as anodes in solid oxide fuel cells, which must work at temperatures between 500ºC and 1000ºC. This must be a porous material that is a good electrical conductor and resistant to a highly reducing environment. A yttria-stabilised cricone cermet with 30% nickel metal particles and 30% pores has been chosen.

Work is also being done on the development of fire resistant materials. The main application here is the development of building materials that can withstand the high temperatures that develop during a fire and allow structures to remain stable for a longer period of time.

New electrical patterns based on quantum phenomena

Our ability to know and change the world is intimately linked to our ability to measure, which consists of finding out how many times a given standard quantity is contained in the quantity we want to quantify.

Metrology is the science of measurement. The ability to make increasingly precise measurements is the basis for many technological advances. But good standards are not enough to measure well. It is within the framework of quantum mechanics that we can go further in the search for precision and universality of measurements.

Based on quantum phenomena, we have developed voltage and electrical resistance standards at the Materials Science Institute of Aragon. And by using properties of superconducting materials, we have developed new measurement bridges that allow the new standards to be used without degrading their accuracy during measurements. One of these systems may in the future form part of a new quantum current standard.

More information: New electrical standards based on quantum phenomena

Biophysics research: simple models for complex behaviour.

Sixty years ago, Erwin Schrödinger, a pioneer of quantum physics, in his book What is Life? posed the question Is life based on the laws of physics? Since then, and motivated to answer this question, many physicists have devoted all or part of their research to integrating the complexity of biological systems within the framework of the laws of physics (Francis Crick, co-discoverer of the structure of DNA, is the most representative example). This phenomenon is especially relevant in the last 20 years, when some fields of physics have converged, such as what has come to be known as Soft Condensed Matter Physics with the biology of biological macromolecules: proteins and nucleic acids.

The Statistical and Nonlinear Physics group has recently been working on different examples of physical modelling of biological systems occurring at different length (or abstraction, if you prefer) scales. Examples include the modelling of molecular motors, DNA models and the simulation of protein dynamics.

More information: Biophysics research: simple models for complex behaviour.

Photonics

In the 1960s Gordon Moore of Intel predicted that the number of electronic components on a microchip would double every 18 months: it’s true. As a result, we are getting faster and faster computers, operating at 1GHz, but will we ever see one that operates at 100 GHz? Possibly not. In fact, even producing one that runs at 10 GHz faces significant, if not insurmountable, technical impossibilities. However, if we use photons, light, instead of electrons to transmit signals, it would be possible to build a computer operating at 100 THz, or 100,000 GHz.

At present, the performance of electronic instruments depends on the connections between different chips and other devices rather than on the chips themselves. But experts suggest that within a decade, as we become more and more miniaturised, the bits of metal used to connect the various components of a chip will suffer from increasing problems such as loss of speed. Using optical connections would be an alternative because they don’t have these problems.

Part of this amazing new world, photonics, will be built using optical components made from so-called photonic and quasi-photonic crystals, materials whose structure can be manipulated to control and guide the propagation of light on a microscopic scale. However, achieving photon-only electronics may be a long way off, if ever. The euphoria of the 1990s, which saw the construction of an optical computer just around the corner, had to be tempered by a fundamental problem: there are no optical systems that perform functions equivalent to classical integrated circuits in electronics. Today, enthusiasm has been tempered and research is being carried out into the design of circuits that use both: optoelectronics. This will provide the essential bridge linking electronics with photonics and optical communications.

However, not just any material can be used. Since the microelectronics industry uses silicon, any device that wants to be integrated into this world must be made of silicon. And here lies one of the main drawbacks. Most optoelectronic components can be made from silicon, but a complete optoelectronic system is elusive because one crucial component is missing: a light source made from silicon. A laser built using conventional silicon technologies would make a tremendous impact. That this has not been achieved is because the electronic structure of silicon is not suitable for light amplification, a basic feature for any laser.

But the surprises do not end there. In 1998 Thomas Ebbesen of the NEC Research Institute in New Jersey made an astonishing discovery: suppose a silver-coated quartz sheet with a series of tiny holes, 150 nanometres in size. We then shine an appropriate light on it (technically, with a wavelength 10 times the size of the holes). Expected: practically not much light is transmitted to the other side. Observed: a lot of light passed through. The astonishing thing: more light passed through than was incident on the hole. In other words, the hole behaves like a funnel that collects light from nearby surroundings and passes it to the other side. At INMA, we have even managed to get more light through than in the original experiment. The applications of this discovery are immense.

Controlling light with nanostructured metals

Metals reflect light but they also have another, less well-known optical property: under certain conditions light can travel along a metal surface, without moving away from it. This is a very peculiar property as light normally travels through the 3 dimensions of space and confining it is not easy. In fact, this ‘surface light’ is a more complicated wave than normal light because it involves both electric and magnetic fields and the free electrons present in metals; technically, it is known as a ‘surface plasmon’ (SP).

Until very recently, we did not know how to control the movement of this light, which was eventually lost as heat. But recently, great advances have been made in controlling the propagation of this light, and how to extract it in a useful way, opening up the possibility of using these advances in high-speed optoelectronic devices.

Nanomaterials

In Philadelphia in 1946, the world’s first computer was built. It was called the ENIAC, was over three metres long and consumed 174,000 watts of power: every time it was plugged in, the lights of Philadelphia flickered for a few moments. Today we have computers that fit in the palm of your hand and run on batteries.

Miniaturisation is reaching unimaginable extremes, to the point where we are making objects 100 times smaller than a virus: we are in the age of nanotechnology. Using nanoscience, NASA has been able to detect ONE water molecule on Mars.

What are we doing at INMA on this topic?

We build magnetic nanowires -for sensors with a reaction time of millionths of a second-, we study materials containing magnetic nanoparticles -applicable in the read heads of hard disks-, nanoporous materials -used in the fractionation of oil-, and even the metabolism of iron in humans, where nanoscience has a lot to say…

We are investigating the use of magnetic nanomaterials in medicine: they can guide the drug to the site of application by finding the most suitable molecular pathways. We are also researching nanomaterials with a magnetocaloric effect, which can be used to clear tumours in areas where surgery is risky or impractical.

We are also working in one of the most promising fields, that of carbon nanotubes. They are 6 times less dense than steel, 5 times more rigid and 100 times more resistant. The INMA is working to incorporate them into a nanocomposite of very high mechanical performance.

Magnetism as a tool in the study of new alloys

Why are we still fascinated by metals? Dozens of centuries after their discovery, metallic materials continue to play an important role in our economic and technological development. Despite the remoteness of our coexistence with them, there are still many basic aspects yet to be fully understood, such as the emergence of new manufacturing methods, which require innovative approaches to the characterisation and understanding of these materials.

Magnetic tracking of the growth of cobalt particles in a CuCo matrix illustrates this new approach, which is being worked on at INMA. Surprising details of how the cobalt particles cannibalise their environment until they become magnetically isolated from the rest will allow us to perceive why the use of magnetism can be a refined tool in the characterisation of alloys of industrial interest.

More information: Aragón Investiga

Spintronics: spin control

Traditional electronics based on semiconductor materials and developed over the last 60 years are based on the control of the charge of the carriers (electrons or holes) while the spin of the carrier plays no relevant role (spin is a quantum-mechanical property of particles and atoms). In the last 15 years we have seen an explosion of new electronic devices (some of them only theoretically proposed, others already commercialised) based on electron spin control. Spin control is generally achieved by means of a magnetic field and has led to the birth of ‘magnetoelectronics’ or ‘spintronics’. Some of the magnetoelectronic devices already on the market today are the magnetoresistive read heads that we use to read the magnetically stored information on our computer hard disks and non-contact position sensors for automobiles in the field of safety and comfort.

In the near future, non-volatile magnetic memories based on ‘magnetic tunnel junctions’ will be commercialised for application in computer RAMs and in memories for digital cameras, mobile phones, etc.

More information: Spintronic: spin control

Instituto de Nanociencia y Materiales de Aragón