Register for an account


Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.


Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

The Sciences

A New Way to See Magnetic Fields

Using neutrons, materials scientists develop a method that goes below the surface.

By Anna FunkFebruary 11, 2019 6:00 PM
Magnetic Fields - Nature CCBY
(Credit: Manke et al. 2018 Nature Communications, CC-BY 4.0)


Sign up for our email newsletter for the latest science news

Although it might not be obvious, a material like lead has multiple magnetic fields, one inside and another on its surface. Until recently, researchers could confidently measure only surface fields. Now, in a recent Nature Communications paper, materials scientists in Germany describe a way to create detailed maps of the direction and strength of magnetic fields inside bulky materials like those used in electric engines and high-efficiency transformers.

The new method uses neutrons, neutrally charged subatomic particles that spin in the opposite direction of a magnetic field’s alignment. Because neutrons are so small and chargeless, they easily penetrate many materials. The team took advantage of these properties, scanning a sample of lead with neutrons that all had the same spin. When they hit a magnetic field inside the sample, their spin changed detectably, letting researchers plot the information.

The image shows the magnetic field in and around the lead sample (outlined in white). Warmer colors denote stronger sections of the magnetic field.

[This story originally appeared in print as "Inner Magnetism."]

3 Free Articles Left

Want it all? Get unlimited access when you subscribe.


Already a subscriber? Register or Log In

Want unlimited access?

Subscribe today and save 70%


Already a subscriber? Register or Log In