Magneto-optical Kerr Effect Magnetometer (MOKE)
The majority of the magnetometry is carried out by using our home-built MOKE system that can achieve fields of 0.8 Tesla. The system is capable of measuring single magnetic nanostructures such as magnetic nanowires and artificial spin-ice unit cells (see Fig above). We have also recently used the system to measure our first 3D magnetic nanostructures.
Two-photon Lithography System
The system is able to write 3D nanostructured patterns down to resolution of 200nm into conventional photoresists. The system utilises a 780nm, 120mW femtosecond laser which is focussed down to a diffraction limited spot within the resist. There are two ways to expose a pattern. Firstly, we can use piezos with 5nm resolution in order to move the sample with respect to the laser spot. Secondly we can utilise galvo-scanners in order to steer the laser beam at speeds of mm per second.
Class 1000 Cleanroom Booth and Associated Equipment
Our two-photon lithography system is housed within a class 1000 cleanroom booth that is also home to other fabrication facilities such as spin-coater, hot plates, ultrasonic baths and compressed air. This allows all fabrication to take place within our laboratory.
Zeiss Axio Imager Optical Microscope
Also within our laboratory this enables us to do quick and routine inspection of our lithographically written samples. This is used both to inspect patterns before electrodeposition of magnetic material and also to take high resolution images of final samples.
Montana Cryogen-free Cryostat
Our MOKE system is also home to a Montana optical cryostat allowing our magnetometry measurements to be performed between 3.5 to 300K. The system also has electrical connections allowing the measurement of temperature dependent resistivity and magnetotransport. The system is completely cryogen free and achieves base temperature within 4 hours.