Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Three-dimensional imaging – first insights into magnetic fields

31.03.2008
3-D images are not only useful in medicine; the observation of internal structures is also invaluable in many other fields of scientific investigation.

Recently, researchers from the Hahn-Meitner-Institute (HMI) in Berlin in cooperation with the University of Aplied Science in Berlin have succeeded, for the first time, in a direct, three-dimensional visualisation of magnetic fields inside solid, non-transparent materials. This is announced by Nikolay Kardjilov and colleagues in the current issue of the journal Nature Physics, the on-line contributions to which will be released in advance on the 30th of March at 18.00 London time.


Three-dimensional imaging of magnetic fields with polarized neutrons. Hahn–Meitner Institute

The researchers in the imaging group used neutrons, subatomic particles that have zero net charge, but do have a magnetic moment, making them ideal for investigating magnetic phenomena in magnetic materials. When in an external magnetic field, the neutrons behave like compass needles, all aligning to point on the direction of the field. Neutrons also have an internal angular momentum, often referred to by physicists as spin, a property that causes the needle to rotate around the magnetic field, similar to the way in which the Earth rotates on its axis. When all of the magnetic moments point in the same direction then the neutrons are said to be spin-polarised. If a magnetic sample is irradiated with such neutrons, the magnetic moments of the neutrons will begin to rotate around the magnetic fields they encounter in the sample and the direction of their spin changes.

Kardjilov's group used this phenomenon as a measurement parameter for tomography experiments using two spin polarisers (which only allow the passage of neutrons whose spin points in a specific direction) to polarise and then analyse the neutrons. By detecting changes in the spins, it is possible to “see” the magnetic fields within the sample.

Kardjilov explains this by comparison with a medical CT scan; when a specimen is irradiated with x rays the density of the materials present alters the intensity of the light. "It's the same with our magnetic specimen, which changes the spin rotation of the neutrons", says Nikolay Kardjilov. "The equipment only allows passage of neutrons with a specific spin rotation, and this generates the contrast according to how the magnetic properties are distributed within the specimen. By rotating the specimen we can reconstruct a three-dimensional image."

Since 2005, Nikolay Kardjilov has built up the neutron tomography section at HMI and now his group is the first to use spin rotation as a measurement signal for three-dimensional imaging. Normally, neutron imaging relies on the different levels of absorption of radiation by different materials to produce contrast. The measurement of magnetic signals is a novel concept and its success lies partly in the polarisers and analysers, and the detector system, which have been developed and built by the HMI researchers.

Magnetism is one of the central research fields at HMI. To understand high temperature superconductivity, for example, it is vital to understand how magnetic flux lines are distributed and how these flux lines can be established in the material. With Kardjilov's experimental setup, it is now possible, among other things, to visualise magnetic domains in magnetic crystals three-dimensionally.

At Hahn-Meitner-Institut in Berlin work about 800 employees, among them about 300 scientists. They research properties of materials, develop solar cells of new generation and practice a user facility at research reactor BER II open to the national and international community.

To 1. Januar 2009 the HMI will merge with BESSY, the Berliner Elektronenspeicherring- Gesellschaft für Synchrotronstrahlung becoming together a new research center, the Helmholtz-Zentrum Berlin for materials and energy.

The Hahn-Meitner-Institut Berlin is member of the Helmholtz-Association, the biggest german research organisation. It involves 15 research institutes and 24.000 employees.

contact: HMI
Glienicker Str. 100
14109 Berlin
Dr. Nikolay Kardjilov
Tel.:8062-2298
e-mail: kardjilov@hmi.de
Press and PR:
Dr. Ina Helms
Tel.: 8062-2034
e-mail:ina.helms@hmi.de

Dr. Nikolay Kardjilov | alfa
Further information:
http://www.hmi.de/people/manke/bildernatphys/

More articles from Physics and Astronomy:

nachricht The taming of the light screw
22.03.2019 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht Magnetic micro-boats
21.03.2019 | Max-Planck-Institut für Polymerforschung

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>