Magnetostriction.
| FEATURES | NIJMEGEN | DRESDEN |
|---|---|---|
| Local Contact | Steffen WIEDMANN |
Yurii Skourski |
| Description | An optical fiber Bragg grating (FBG) method developed at the HLD is used to measure magnetostriction in pulsed magnetic fields. The relative length change ΔL/L can be obtained from the shift of the wavelength of the reflected light in the FBG [1].
(left) structure of an optical fiber Bragg grating, (right) principle of the measurement. |
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| Field range | 0 … 30 T (50 mm bore); 0 ... 38 T (32 mm bore) | 0 ... 85 T. This technique can be used in all our magnets. |
| Temperature range | 0.3 ... 4.2 K (3He system) in 50 mm bore 1.2 K … 300 K (4He system) in 50 mm bore 1.2 K … 30 K (4He system) in 32 mm bore | Standard temperature range is 1.4 – 300 K. Measurements down to ~0.6 K with a 3He system are also possible. |
| Sample size | i) in 50 mm bore < 4x4 mm2, thickness L < 3 mm ii) in 32 mm bore < 2x2 mm2, thickness L < 1.5 mm | The sample size should be > 1 mm. The samples can be mounted with a defined orientation |
| Sensitivity | Resolutions of about ΔL/L ~ 10-7 are achievable. | |
| Typical experiments | ΔL/L(B) - magnetostriction at constant T: |
Magnetostriction of GdSb single crystal measured in pulsed magnetic fields [1] |
| Sample Holder | 
(left) dilatometer for 50 mm bore, (middle) dilatometer for 32 mm bore, (right) dilatometer for 32 mm bore on stick. |
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| Sample environment | Gaseous helium from 270 K down to 4 K, liquid helium below | |
| Measurement Examples | The world’s smallest capacitive dilatometer: Review of Scientific Instruments 88 (2017), 083903; Field-induced states of graphite: Nature Communications 8 (2017), 1337; Lead halide perovskites: Advanced Materials 31 (2019), 1900521; Negative Thermal Expansion in frustrated spinel: Physical Review Letters 123 (2019), 027205; | [1] R. Daou et al., Rev.Sci Instum. 81, 033909 (2010) |