Home
-Introduction
-Contact
-C.V.
Research
-News
-Data&Video
Teaching
The Group
- Members
- Lab projects
- FY projects
- Info for students
- Join
- Former Members
Publications
Internal (Wiki)
Here we will give some further info on our work on magnetic bubbles which will soon be published in Physical Review Letters.The manuscript of the unedited article is available here.
You might wonder how magnetic bubbles look alike and how large they are. Here is a picture taken with a microscope from the top on a droplet with a few bubbles. We are looking from the top onto the floating bubbles.
The bubble consists of air and a thin shell of nanoparticles. The thickness of the shell is about the wavelength of light. That is why they look so shiney in the picture above.
The shell consists of many layers of nanoparticles. A cut through the cross section as viewed with an scanning electron microsocpe:
So what can you do with a magnetic bubble?
Clearly you can have some fun, just use a magnet and move the bubble downwards...
But that is not all, the bubble remains elastic such that it responds to a change in the ambient pressure. Indeed, the bubble is quite musical and has its own favoirte frequency. Here is a movie showing a bubble to oscillate at a beat of 27,000 times per second (27 kHZ).
And, yes you can do something useful with this research result. You can stir liquid. The following movie shows a bubble oscillating to the sound field as above but we added some tracers to the liquid. The bubble creates a streaming flow. You see, once the sound field is off the mixing flow stops, then we move the bubble with a magnet and switch on the sound. The flow pattern just appears again.
We envision a remotely powered device which can be used to steer tiny amounts of liquid in microfluidic application or create some stimulus to cells for in vitro biomedical treatment.
Our next goal is a magnetic bubble trap...
As last, the recipe to make these bubbles is rather simple. You can make them in every better equipped kitchen. The details are available here.