0.7 a 0.6 ≌月=日 0.5 0.4 B=0;,B△=100 gauss 0.3 60.2 B=500 gauss 0.1 T1 25 T in mK Figure 12.8 Entropy for a spin 2 system as a function of temperature, assuming an internal random magnetic field Ba of 100 gauss. The specimen is magnetized isothermally along ab, and is then insulated thermally. The external magnetic field is turned off along be. In order to keep the figure on a reasonable scale the initial temperature T, and the external magnetic field are lower than would be used in practice