Magneto-Optic Module

Documentation

Product Name
Magneto-Optic Module
Overview
Magneto-Optic Module is compatible with our 50mm CryoAdvance model. Allows for a 0.7T magnetic field applies across a sample. Includes vacuum housing with 3 available optical ports and two ports occupied by the integrated magnet pole tips. This kit includes one pair of single-piece, detachable magnetic pole tips, AR-coated fused-silica windows, the Magneto-Optic radiation shield, a sample mount, bipolar power supply, and closed-cycle chiller. A second configuration is available to enable low working distance applications. It includes raised pole tips and the Recessed Window Port Accessory.
Documents
Magneto-Optic User Manual v. 2.1
Download

Specifications

Sample Environment

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)
Cryostation -lifting off lid
Cryostation -lifting off lid
Cryostation -lifting off lid
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.
Cryostation -lifting off lid
Raised Pole Tips
Lens Pole Tips
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

Magnet Performance

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)
Cryostation -lifting off lid
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
Cryostation -lifting off lid
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
Cryostation -lifting off lid

Performance Data

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.

B-I Curve

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.

B-I Curve
Field Uniformity

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.

Radial

Field Uniformity Radial

X-Axis

Field Uniformity X
AC Magnetic Disturbance
AC Magnetic Disturbance

Video Guides

Guide
Description
Cryostation® Magneto-Optic Module: Low Temperature Magnetic Field Control
Overview of the Magneto-Optic for the Cryostation®. The Magneto-Optic module adds up to a 0.7T magnetic field to the cryogenic sample space while maintaining side and overhead optical access.