Cryostrain: a cryogenic uniaxial strain cell
Apply continuously tunable tensile and compressive strains within a cryogenic environment. Suitable for use with scanning probe and confocal microscopy, x-ray and neutron scattering, resistivity, susceptibility and many other measurement techniques. This product is a component for use with a wide range of commercial or home-built cryogenic measurement systems.
- Apply precise, continuously tunable, compressive and tensile strains to samples at cryogenic temperature; without a mechanical feed-through.
- Highly compact, the entire product range is designed to fit vertically inside a 1" (26 mm) bore (for example a PPMS®) with the smallest size (CS100) being also able to fit horizontally in this tiny space.
- Temperature compensated – applied strain can be kept constant over a wide temperature range.
- Operates down to temperatures of below 1 K and in high magnetic field.
- High strains possible (typically limited only by sample buckling/breaking).
- Wide angle of access to sample. Suitable for cryogenic scanning probe microscopy
Match theory to experiment
Significant recent research effort has been spent investigating the electronic and magnetic properties of materials when subjected to uniaxial strains because it allows a convenient way to compare structure/property relationships as predicted from theory experimentally. See Uniaxial Strain in Condensed Matter Physics.
Compatible with a wide range of probes
The cryostrain cell is the ideal component for your cryogenic measurement system - compatible with a wide variety of different probes, including x-ray diffraction, scanning probe microscopy, optical imaging and electrical measurements.
Complementary to existing techniques
The cryostrain cells is an ideal companion to diamond anvil cells, providing a complementary technique while also offering better sample access, positive and negative stresses, and in-situ tunability.
A tried and tested technology
The Cryostrain family is based on a technology that has been used in an laboratory environment for more than two years leading to several publications, including a recent high profile paper in the journal science.
|Maximum sample spring constant1||5 × 106 N/m||5 × 106 N/m||3.5× 106 N/m||2.6 × 106 N/m|
|Intended Sample Size2||Cross-section |
|Operating Temperature||Less than 300mK-400K|
|Maximum applied displacement at zero load||Room temperature (at -20V/+120V)|
Cryogenic temperature ( at ±200 V)
|±6 µm (12 µm total range)|
±3 µm( 6 µm total range)
|±7 µm (15 µm total range)|
±4 µm( 8 µm total range)
|±13µm (25 µm total range)|
±7 µm( 14 µm total range)
|±17 µm (34µm total range)
±10 µm( 20 µm total range)
|Titanium, unalloyed (Grade 2)
|4 HV cables3
|Feedback Sensor||Capacitive - resolution 0.1 nm to 10 nm depending on the capacitance bridge used.|
1These maximum values are only for when the cell is used to its maximum room-temperature displacement. For smaller displacements stiffer samples may be used. See the graph below for guidance.
2Sample cross sectional area based on predictions about the spring constant based on typical Young's moduli. Longer samples possible but maximum applied strain will be reduced (strain tuner displacement remains the same).
3Conventional wires can be used up to ~±200 V; contact sales team for more details.
A summary of the values of acceptable sample spring constants and displacements is shown in the graph to the left.
It follows that large displacements require larger cells, with the CS130 offering the largest displacements. These larger displacements will also cause larger forces within the cell for a given sample spring constant (Hooke’s Law). At a given internal force, the strain cell may be damaged. Thus to remain under this maximum internal force, a larger cell must either apply less than the maximum displacement or samples must be used with smaller spring constants. For smaller displacements, the internal forces never reach this threshold but there is still an upper limit of 5x106 N/M as overly stiff samples will cause an unacceptable amount of twisting in the cell which will affect the accuracy of the position sensor.
To the left shows is an illustration of the CS100 cell. The diagram illustrates the movements in the strain cell when the sample is subjected to positive and negative strains. For demonstration purposes, the movements depicted in the figure have been highly exaggerated.
Piezoelectric stacks lengthen in their polling direction upon cooling. This lengthening is many times longer than the stroke length of the stack, meaning that unless steps are taken, the strain cannot be adequately controlled when the temperature changes. The Cryostrain family of strain cells overcomes this issue with an arrangement of piezoelectric stacks that allows the thermal expansion to cancel out leaving the strain to unaffected by the thermal elongation of the stacks.
Aside from thermal compensation, having pairs of stacks working in opposition to each other means that higher displacements can be generated compared to a single piezoelectric stack glued directly onto the sample; a valuable improvement considering the intrinsically short piezoelectric stroke lengths.
Great access to the strained sample
Mounting the sample on the very top face of the sample maximises the angle of access. For example a scanning probe tip could scan the surface while the sample is mounted on the strain cell.
For best results we recommend that customers use the cells with the following equipment;
- A Razorbill Instruments RP100 power supply is compatible with all four CS1XX strain cell models. This power supply can supply low-noise four quadrant, sink/source voltages of ±200V.
- Use of the feedback sensor requires the detection of an approximately 1 pF capacitance. A good option, that offers sub-10nm displacement sensing is the Keysight E4980AL (20 Hz to 300 kHz).
CS1X0 datasheets, dimensioned drawings and 3D CAD files
These datasheets contain everything you need to get started with one of our products.
These dimensioned drawings and CAD models will enable you to determine your preferred way to mount the cell in your cryostat.
To download the .STEP files, please right-click on the the download link and select "save link as..." then select where you want to save the file, specifying a .step filetype.
|CS1X0 dimensioned drawings: device|
|CS1X0 dimensioned drawings: sample plates and spacers|
|CS100 3D .STEP file|
|CS110 3D .STEP file|
|CS120 3D .STEP file|
|CS130 3D .STEP file|
We have a large number of additional resources on our downloads page, including a guide to mounting samples and various resources to help you integrate your strain cell with your cryostat.
To access our download page, please fill in your details into the form below.
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