Monopolar mania

Once long ago, I sat on my toilet bowl back in Chip Bee Gardens and thought about the greatest things that God created.  I came to the conclusion that two of the greatest things God created were 1) the most basic unit of matter, 2) water.

I continue to be fascinated with these, and as my scientific understanding grows, so does my sense of wonderment.  From atoms to sub-atomic particles, to the gradual melding of our disparate concepts of energy and particle in physics, the recent interesting advancements in physics suggest that the most basic unit of matter is not dots, or atoms, but string.  Our best analogy or understanding of the wave-particle duality of matter is that of a piece of string that indicates the probable positions of a particle's trajectory.  

As for water, as I began to understand the intricacies of hydrogen-bonding, my appreciation of the molecule reached new depths.  The way the specific properties of the elements hydrogen and oxygen result in dipole formation, that results in bonding that leads to water's unique and anomalous properties is nothing short of miraculous in its simple ingenious logic.

Today, I found something that fused my two pet topics (quantum physics and water).  Forget bipolar magnetism, monopoles are the next big thing in physics, and it seems dreadfully exciting.  It's based on the way chaotic way in which certain molecules are organised when in crystal lattice.

Monopoles are found in a substance known as spin ice (holmium titanate), which organises itself in a way that is configurationally similar to ice due to the properties of holomium, titanium and oxygen.  

Holmium ions align their spins more than twice as readily as even iron does, but in holmium titanate, the titanium and oxygen atoms form a tight tetrahedral lattice with holmium ions at the corners (see diagram). Thus corralled, the ions cannot align their spins all in one direction, so plump for the next best thing: two spins pointing inwards to the centre of the tetrahedron, and two pointing out. "

It's an unhappy arrangement. The spins don't know where to go," says Oleg Tchernyshyov of Johns Hopkins University in Baltimore, Maryland, who studies similar instances of magnetic frustration.

The spin arrangement in holmium titanate mirrors the way that hydrogen ions are arranged in water ice, so Harris and Bramwell coined the term "spin ice" to describe their compound.

 - Newscientist.com