Examining the world of the very, very small is a wonderland for physicists; at this nanoscale, where materials as thin as 100 atoms are studied, totally new and unexpected phenomena are discovered.  Here, nature stops behaving in a way that is predictable by the macroscopic law of physics, unlike what goes on in the world around us or out in the cosmos. 

Everybody knows how magnets work, but nanomagnets are much different. A nanomagnet is a submicrometric system that presents spontaneous magnetic order (magnetization) at zero-applied magnetic field (remanence, or the magnetization left behind in a ferromagnetic material (such as iron) after an external magnetic field is removed).

The tiny size of nanomagnets prevents the formation of magnetic domains – the region within a magnetic material in which the magnetization is in a uniform direction. This means that the individual magnetic moments of the atoms are aligned with one another, and they point in the same direction.

The ultimate limit in miniaturization of nanomagnets was achieved in 2016; individual Holmium atoms present remanence when deposited on an atomically thin layer of magnesium oxide coating a silver film was reported by scientists in Switzerland. 

In a new study published in the prestigious journal Nano Letters under the title “Interior and Edge Magnetization in Thin Exfoliated CrGeTe3 Films,” Dr. Yonathan Anahory at Hebrew University of Jerusalem (HUJI)’s Racah Institute of Physics described his astonishment when looking at images of the magnetism generated by nano-magnets. He led the research team, which included doctoral student Avia Noah.  “It was the first time we saw a magnet behaving this way,” he said as he described the images that revealed the phenomenon of “edge magnetism.” 

This nano-effect, although very small, could actually have broad applications in our daily lives.  “In today’s technological race to make every component smaller and more energy-efficient, the effort is focused towards small magnets with different shapes,” Anahory noted. 

The new edge magnetism offers the possibility of making long wire magnets only 10 nanometers thick that could curve into any shape. “It could revolutionize the way we make spintronics devices,” added Anahory, referring to the next-generation nano-electronic devices with reduced power consumption and increased memory and processing capabilities  

Images showed that the magnetic material the HU researchers were studying retained magnetism only on its edge, only within 10 nanometers of the edge (remember, a human hair is around 100 000 nanometers). 

The actual discovery of edge magnetism was somewhat serendipitous: Anahory decided to look at a new magnetic nano-material (CGT) produced by his colleague at Spain’s Universidad Autónoma de Madrid. The discovery ultimately relied on images made by a new type of magnetic microscopy developed in Israel that can measure the magnetic field of a single electron.  Discovering new phenomena relies on highly sophisticated new technologies.  Further, the phenomena themselves will be at the heart of even more advanced technologies, as edge magnetism has demonstrated, he concluded.