Single Molecule Magnet Einstein-de Haas Effect

Albert Einstein despite being a physicist only ever published one experimental paper; that being a description of the Einstein-de Haas effect. If a ferromagnetic material is suspended in a magnetic field that then changes direction a torque is created by the conservation of angular momentum for each electron spin in the metal. The effect proves that electrons are the producers of electric currents and that spin angular momentum is analogous to macro angular momentum. This, until recently, had only ever been observed in macromaterials however although theoretically the same thing should happen with a tiny magnet even one made out of a single molecule. And now it has been done. Using a single molecule magnet formed out of terbium and policium surrounded by a ligand shell the same conservation laws applied and by a phonon interaction (excitation of atoms in a lattice) it could be observed that the molecule rotated. This experiment confirms the theoretical predictions made over a hundred years ago with the original  Einstein-de Haas  Einstein-de Haas experiment and appears to make a link between quantum tunneling and angular momentum as the molecules ability to tunnel seemed to be completely suppressed while interacting in the magnetic field. Some theoretical explanations are already being given but lets hope we don’t have to wait a century before some of these theories can be proven.


Sensing New Sources Of Neutrinos

Neutrinos are possibly the least understood fundamental particle in the standard model and research is constantly going on to find out more about them. The 2015 Nobel prize for physics was awarded for the discovery of neutrino oscillations  and the the conclusion that neutrinos must have mass. Despite this the fact that neutrinos don’t interact with very much and move very fast makes them hard to pin down even though they are the second most abundant particle in the universe (after the photon). It was only in 2013 that we gained the ability to observe extragalactic neutrinos and even then only the most high energy ones. But now the antarctic research base has detected a phenomenon that they already had a code name for. A super high energy neutrino with over two quadrillion (short scale) electron volts (1015eV).This particle named Big Bird after the sesame street character has now pushed the upper limit for the energy of neutrinos and the challenge is now to find the source. Looking at the extremes is what astrophysicists do best and through this we gain a greater understanding of how our universe came to be in the first place.

Sperm Made From Skin Cells

It is estimated that worldwide about ten to twenty percent of couples are unable to have children due to ineffective gametes. Either the ovum, or system to develop the ovum is faulty or the sperm may not be in great enough numbers or lack the mitochondria to make it likely that meiosis will ever occur. Methods like in vitro fertilisation have made it possible for women who were originally infertile to have children and now a similar method is being developed for men. In 2012 it was proven that theoretically any cell with the right chemical treatment can return to an embryonic stem cell and so scientists in Spain are attempting to take this idea and reinvent the cells as working gametes. They have not yet managed to make a sperm that could actually fertilise an egg, merely a germ cell with the potential of growing into a working sperm. This took a month of careful culturing to produce and to develop a fully working gamete will require much further maturing and the overcoming of a series of ethical issues. Since the exact same process can be used to produce an egg cell it would be possible when the research is complete to completely develop a fetus from only a skin sample of a mother and father. Many countries have laws about artificial embryos and their production so this research will likely have to ask for permission from a government medical council before it can begin to fully bloom.

Fluid Pressure In Fault Lines

When an earthquake occurs it is because two of the Earth’s tectonic plates are either pushing against each other or sliding past each other. Pressure builds as the rock is deformed until eventually, like a piece of elastic, it springs back and this mass movement is what causes an earthquake. What I have just described is a very simple model and is worthless when it comes to making predictions about earthquakes until more details are added. The roll of water in this action was believed to be understood for quite a while. Water lubricates the fault and makes the slip more likely to happen as well as the internal pressure of the water reduces the pressure the two plates are pressing against each other with. This is actually a good thing because it means less energy can be stored before the plates slip past each other called “stable sliding,” that doesn’t cause and earthquake. But this idea is getting turned on its head as recent models suggest that a decrease in water pressure actually stimulates more stable slipping. To see if this idea was accurate researchers decided to perform some of the first laboratory fluid pressure studies. Their results were very interesting. By using a massive machine that recreated both the normal and sheer stresses at a fault and then pumping pressurised water in they could see how this affected the friction between the test plates in the machine. Their results actually appear to prove both sides of the argument as they discovered the critical slip distance as well as the velocity strengthening of the pressure actually is based on the range in which the pressure resides. This means between certain parameters the increased water pressure can be expected to reduce friction but between another set it may be neutral or actually increase it. Determining when these parameters come into affect is the new goal for the research.

X-Rays Visualising Viruses

Development of a new type of laser that uses electrons moving through a magnetic material as its medium to amplify the light is planned to be used on viewing and mapping the structure of objects from the micrometer (1×106) to the angstrom (1×10 10)scale. These lasers are known as X-Ray, Free Electron Lasers and are more powerful in both amplitude and coherence then others of their size. When X-Rays are normally used for analysis it is part of X-Ray crystallography which, as the name suggests, requires whatever is being analysed to be in a crystal form. These new lasers however are hoped to be able to collect data on viruses and other biological particles in a common state, the way they normally interact. The disadvantage of this method is that it is very slow. Without the reliable order of a crystal the particle has to be blasted again and again with the X-Rays to get a proper diffraction pattern. The research showed  that about 200,000 diffraction patterns were required to get an accurate 3D reconstruction of the test protein requiring about two hours of exposure at the European X-Ray Free Electron Laser. It should be noted however that an analysis of this detail would require forty eight hours in a traditional laser source. But now the framework is in place for the experimental use of this technique in a real analytical situation with only further development planned for the future.

Weekly Roundup 16

This week a solar power plane was able to cross the pacific in three days and will continue on its mission to fly around the entire world. This was the most risky part of the journey but with it completed it won’t be long until the pilots are safely home. In a semi related story a massive breakthrough in the materials used to create solar cells is going to give a massive boost to their efficiency. Apart from that the research engine has continued chugging along as ever. Now for an interesting fact. The date this post was written is the 24th of April, is the official date for the destruction of Troy in 1184BC. The Ancient Greeks are the bedrock (along with the bible) on which most of western culture is based. Their politics, especially the Athenian idea of democracy, still holds as a uniting principle. Their philosophy regarding metaphysics and theoretical mathematics still holds an essence after all these centuries. And finally their scientific knowledge was of course incredibly advanced for such a civilisation. Even in primitive dialect they explained many concepts that we now know were roughly correct. For instance Aristotle believed that earthquakes and volcanoes were caused by turbulence within the earth; but of heated air not molten rock. The biologists believed their to be a magical essence that flowed through our bodies to produce life; but believed the liver pumped when we now know the heart would have been a better guess. Every one of these theories shunted us on the way to our understanding and maybe in another 2000 years we’ll be seen as ridiculous. But we can always hope for brilliant and ridiculous can’t we.

Conservation In Organic Semicondcutors

Organic semiconductors are semiconductors comprising of atoms that chemists normally define as organic. Mostly carbon and hydrogen but sometimes oxygen, nitrogen and sulphur are added for specific properties. As they are a relatively new invention few people have any ideas about how charge actually moves through the lattice on a theoretical level. By applying the basic laws of conservation of energy and momentum researchers have attempted to both discover new affects of organic semiconductors and simultaneously create a theoretical model for how they work. It had been previously observed the importance of temperature on the activation energy of the semiconductors, the hotter the lattice and higher the voltage the faster the charge carriers moved. This is more than in normal semiconductors and by applying the conservation laws the maths shows that while the voltage is applied the electrons gain more energy and raise to higher temperature than their surroundings. This makes the activation energy (difference between ground and Fermi energy) much easier to achieve then would otherwise be the case. This new theory reflects experimental research better than its more primitive predecessor and also gives predictions that can be tested. By doing this, the theory will be either proven wright or closer to being wright. Only by constant reimagining can scientific theory continue to remain an advanced and up to date idea.