High resolution thermal expansion studies of some magnetic materials
High resolution thermal expansion studies of some magnetic materials
An automatic, high resolution capacitance bridge has been developed for dilatometry of solids in the temperature range 1.5K to 300K. Detail is given of the design of the bridge, which has a resolution of 1 part in 109 for capacitance values in the range of 10pF to 100pF. In conjunction with a dilatometer mounted in a continuous flow, cryostat measurements have been made on iron difluoride around the Neel temperature. These measurements were used initially to prove the stability, accuracy and repeatability of the results and to refine the experimental procedure. Also, the anisotropy of the magnetic properties of iron difluoride are demonstrated; the transition temperature and the order of the transition are confirmed; and the results are compared with previous heat capacity measurements on this material. Further measurements were made on the two rare earth, noble metal intermetallics: samarium and dysprosium silver. The measurements were again taken around the Neel temperatures. The results for dysprosium silver gave a strong indication of a structural transition prior to the magnetic transition. Again the results for both materials were compared with previous measurements, notably the heat capacity.
University of Southampton
1987
Pulham, Richard Jay
(1987)
High resolution thermal expansion studies of some magnetic materials.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
An automatic, high resolution capacitance bridge has been developed for dilatometry of solids in the temperature range 1.5K to 300K. Detail is given of the design of the bridge, which has a resolution of 1 part in 109 for capacitance values in the range of 10pF to 100pF. In conjunction with a dilatometer mounted in a continuous flow, cryostat measurements have been made on iron difluoride around the Neel temperature. These measurements were used initially to prove the stability, accuracy and repeatability of the results and to refine the experimental procedure. Also, the anisotropy of the magnetic properties of iron difluoride are demonstrated; the transition temperature and the order of the transition are confirmed; and the results are compared with previous heat capacity measurements on this material. Further measurements were made on the two rare earth, noble metal intermetallics: samarium and dysprosium silver. The measurements were again taken around the Neel temperatures. The results for dysprosium silver gave a strong indication of a structural transition prior to the magnetic transition. Again the results for both materials were compared with previous measurements, notably the heat capacity.
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Published date: 1987
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Local EPrints ID: 461845
URI: http://eprints.soton.ac.uk/id/eprint/461845
PURE UUID: dac713c9-3050-4eee-82e4-9095fd582fab
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Date deposited: 04 Jul 2022 18:57
Last modified: 04 Jul 2022 18:57
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Author:
Richard Jay Pulham
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