We report on the realization of a capacitive dilatometer, designed for high-resolution measurements of length changes of a material for temperatures 1.4 K ≤T≤ 300 K and hydrostatic pressure P≤ 250 MPa. Helium (4He) is used as a pressure-transmitting medium, ensuring hydrostatic-pressure conditions. Special emphasis has been given to guarantee, to a good approximation, constant-pressure conditions during temperature sweeps. The performance of the dilatometer is demonstrated by measurements of the coefficient of thermal expansion at pressures P≃ 0.1 MPa (ambient pressure) and 104 MPa on a single crystal of azurite, Cu3(CO3)2(OH)2, a quasi-one-dimensional spin S = 1/2 Heisenberg antiferromagnet. The results indicate a strong effect of pressure on the magnetic interactions in this system.
@article{arxiv.1206.2882,
title = {High-resolution thermal expansion measurements under Helium-gas pressure},
author = {Rudra Sekhar Manna and B. Wolf and M. Souza and M. Lang},
journal= {arXiv preprint arXiv:1206.2882},
year = {2012}
}
Comments
8 pages, 7 figures, published in Rev. Sci. Instrum with minor changes