Dilatometry

MPI-CPfS co-workers: R. Kuechler, M. Brando, F. Steglich

During recent years we have designed, built and patented a new miniature capacitive dilatometer that can fit into a dilution refrigerator as well as into a commercial PPMS. The device is suitable for thermal expansion and magnetostriction measurements from 300 to about 0.03K and in magnetic fields up to 30 T, with a very high resolution of 0.02Å at low temperatures. The main body of the dilatometer is fabricated from a single block of a Be-Cu alloy by electrical discharge milling. The sample is clamped between the two plates of a capacitor whose capacitance changes when the sample expands or contracts. This change in capacitance can be measured very accurately with a commercially available capacitance bridge. Moreover, using a piezoelectric rotator the dilatometer can be rotated 360° inside an inner vacuum chamber of 40mm diameter.

<p>The dilatometer for a dilution refrigerator (left) and for a PPMS (right). This dilatometer enables to measure changes in length of appromimately 0.02Ȧ, (one hundred times smaller than the separations of the atoms in a typical crystal) at temperatures between 300 and 0.03 K and magnetic fields as high as 30 T.</p> Zoom Image

The dilatometer for a dilution refrigerator (left) and for a PPMS (right). This dilatometer enables to measure changes in length of appromimately 0.02Ȧ, (one hundred times smaller than the separations of the atoms in a typical crystal) at temperatures between 300 and 0.03 K and magnetic fields as high as 30 T.

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A compact and miniaturized high resolution capacitance dilatometer for measuring thermal expansion and magnetostrictionR. Küchler, T. Bauer, M. Brando, and F. Steglich, Review of Scientific Instruments 83, 095102 (2012). MPG.PuRe

R. Küchler’s company: http://www.dilatometer.info/

 
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