Starting from the model of Casimir and Du Pré, which has been refined by Eisenstein, an expression for the differential paramagnetic susceptibility of a paramagnetic material, placed in a (gaseous or liquid) bath, is derived. This expression contains among others the coefficient of heat conduction and heat capacity of the surroundings and a heat resistance between sample and bath. Numerical analysis and a short comparison with experiments show that in the temperature region of liquid helium the above-mentioned quantities have a remarkable influence on the dispersion and absorption curves.
Valkering, T. P., & van der Marel, L. C. (1970). On the influence of heat conduction on paramagnetic dispersion and absorption curves. Physica, 47(3), 412-424. https://doi.org/10.1016/0031-8914(70)90273-9