Yujia Teng

A piece of gold doesn't attract paperclips. But if you take a thin film of a gadolinium-gold-germanium alloy and start bending it, magnetic regions can appear. Scientists did this not with their hands, but with a beam of helium ions that penetrated the material through a patterned mask.

The thinner the ferroelectric film, the stronger the depolarizing field — a dictate of classical physics. Imagine a pencil balancing on a fingertip: the shorter it is, the harder to keep it upright. Nanoscale polarization likewise strives to vanish.