Susceptibility and Curie Point of Magnetically Dilute Crystals

The Opechowski calculation of the apparent Curie point, TC, is extended to the case of magnetically dilute f.c.c. crystals. To first order in temperature the result is equivalent to a molecular field treatment. The calculation is carried to fourth order in temperature and a plot is made of TC vs p, the fractional concentration of magnetic atoms. The theoretical result is compared to some existing experimental data and values of the exchange interaction, J, are estimated. The above calculation is found to be useful only for 0.8≤p≤1.0. For low concentrations a crude calculation is made based on clusters of magnetic atoms. To first order in temperature, a linear relationship is found between apparent Curie point and concentration.