This delafossite crystal has four long bars in series made to investigate the in-plane anisotropy.
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About Maja Bachmann
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Entries by Maja Bachmann
The structure was designed to probe the non-local voltage distribution between the lower and upper half of the device.
The FIB is a really versatile tool! Here we used it to mill our group picture into a tiny crystal.
Lamellas can be patterned in complicated shapes and sizes. However sometimes, to understand what’s going on, it’s best to stick to the basics and study simple shapes like a square or a circle. This sample will be cooled down until it becomes superconducting and then will be investigated using scanning SQUID microscopy.
Performing electrical transport measurements under pressure adds an additional level of difficulty to the experiment. This lamella of LaRhIn5 has been welded onto a sapphire substrate with FIB deposited platinum strips to make it more durable and withstand higher pressures.
Measuring anisotropic transport that has a non-trivial angle dependence can be challenging. The FIB is the perfect tool to structure current paths along well defined directions in the crystal. In this device we probe the resistivity at 0, 10, 20 and 30 degrees.
In the ultra-pure metal PdCoO2 the mean free path of electrons is over 20 microns long at low temperatures. In this regime the transport properties are dominated by the ballistic motion of the electrons. Here a single crystal has been patterned into a device where transverse electron focusing can be measured.
For certain applications it’s necessary to extract the lamella out of the crystal for further processing. This can be done in-situ in the FIB using a tungsten needle as a manipulator. Here the lamella has been welded to a copper TEM grid holder and subsequently structured into a transport device.
Cantilevering a lamella off the side of a sapphire piece reduces the coupling to the substrate and eliminates possible strain effects on the measurement. Here a Van der Pauw geometry has been patterned into a lamella of CeIrIn5.
This device was optimised for critical current measurements along two different crystallographic directions. The small cross-section at the constriction of the devices leads to a locally enhanced current density driving the device critical. On the other hand large current contacts reduce the contact resistance and minimise self-heating at the contact injections.