The specific heats of ferromagnetic substances

摘要: It is well known that a close relation must exist between the thermal and magnetic properties of ferromagnetic substance. On basis his theory internal molecular field, Weiss predicted discontinuity in specific heat substance region its critical point. His reasoning may be briefly summarised as follows. The mutual potential energy, E, number elementary magnets, each moment μ making an angle θ with applied field H, given by E = —½ Ʃ H cos θ; so when we consider cubic centimetre write — ½ H. I, where I intensity magnetisation. Since ferromagnetic, suppose, according to Weiss, existence considerable magnitude, equal N constant which obtainable from knowledge Curie point Thus further ½NI2, and, since negative, provide order demagnetise amount necessary 1 gm. therefore 1/2J. N/ᵖ. I2 ᵖ density Now varies temperature, results apparent increase ∂/∂T (1/2J. I2) ∂I2/∂T.