The Susceptibility and Magnetic Specific Heat of Potassium Ferricyanide at Low Temperatures

Abstract

The temperature variation of the susceptibility of single crystals of potassium ferricyanide has been measured between 20° and 1°K, using an a.c. mutual inductance method. The results of measurements along each of the three crystalline axes were fitted to expressions of the form χx = (λx/T)(1 + Δx/T + ...) and values of λx and δx deduced. It was found that the effect of higher order terms was very small. The magnetic specific heat was measured at 1.05°K using the relaxation method. An attempt was made to relate the values of δ to the measured specific heat and paramagnetic resonance line width, on the basis of exchange interaction with n equivalent nearest neighbours. It was found, however, that only approximate agreement could be obtained, and this with the rather small value of n = 2.