Configurable sample space for various experimental requirements
- Unobstructed sample access – the outer (vacuum) lid, magnet poles, and radiation shield are all removable to make sample setup easy
- Adjustable sample space – the side "walls" of the radiation shield adjust in the direction of the magnet axis to accomodate various sample mounting configurations and pole tip options (7mm - 20mm spacing)
Optical access provided by two large side windows, the top, and through bores in the magnet pole axis
- Overhead microscopy – a recessed objective configuration allows for high NA imagining with a short working distance. The recessed top window insert (left image) provides room for bringing an external objective closer to the sample and modified raised pole tips (center image) bring the magnetic field up to the sample.
- Magnet bore optical access - 6mm bores through the center of the magnet poles (right image) provide side optical access for incoming and reflected excitation sources.
Sample mounting and sample motion options available
- Flexible sample mounting options – various sample mounting schemes are available, including a special electrical sample mount for low voltage DC measurements
- Sample motion - the platform and sample space can be configured to accommodate integrated XYZ nanopositioning stages for positional control, as well as piezoelectric or manual rotational stages for varying the angle of the sample with respect to the field
Exchangeable pole tips for adjustable field strengths
- Adjustable field strength – the adjustable radiation shield allows for various pole spacing options down to 12mm (0.7T)
- Concentrated field strength – special threaded extension pole tips extend through the side aperatures of the radiation shield (with windows removed) to focus the field intensity up to 1T (sample temperature will be ~10K with 5mm pole spacing)
Hail probe sensor provided for field calibration
- Accurate field strength – after adjusting the pole tip spacing or sample mounting configuration, the Hall probe fixture calibrates the unit to ensure the maximum field is achieved
Power supply and chiller unit provide magnet control
- Precise magnetic field control – a 500W linear bipolar current source with 20 bit resolution allows fine control of the field strength with a 5 µT step size for studying material transitions near zero or in the presence of a strong field
- Automated software control – current levels are controlled via the standard Cryostation User Interface and can be automated with external scripting
- Operational protection – a closed-loop of special coolant keeps the magnet coils from overheating
0.7 Tesla Bipolar Magnet
A bipolar magnet is integrated directly into the cryogenic sample chamber with fields up to 0.7 Tesla. The unit inserts magnet poles into two of the four standard optical ports, with bores through the magnet cores to allow laser illumination of the sample. The top optical access port can be configured with a recessed objective for low working distance applications.
The field strength depends on the configuration used, with various pole spacing and pole tip options available. An adjustable radiation shield accommodates unique experimental setups, allowing users to expand or resize the sample space or make adjustments to allow for more optical access options.
The maximum field strength depends on the magnet pole tip spacing. Once the spacing is established, the unit is calibrated and the max field can be seen. The typical pole spacing with the radiation shield in place is 12mm, which allows a field of 0.7 Tesla and sample temperatures less than 4K.
The field uniformity varies less than 0.1% in the central 6mm radially with a 12mm pole gap. The measurement below was taken on a system with bore in the magnets.
AC Magnetic Disturbance