Re: Brillouin function for a Ferromagnet

*To*: mathgroup at smc.vnet.net*Subject*: [mg111162] Re: Brillouin function for a Ferromagnet*From*: Themis Matsoukas <tmatsoukas at me.com>*Date*: Thu, 22 Jul 2010 05:43:35 -0400 (EDT)

Your question is ambiguous: 1. Are you using regular math notation, or Mathematica notation? It appears you are using both, which makes it difficult to decipher the meaning of (), [], B_J. 2. Did you mean to say B_J[x]=... ? 3. Is J a known constant, or an unknown to be obtained from the fit? Themis > First I have to apologize if this is too basic for > this forum... I have some temperature dependent > magnetization data from a FeNi-alloy. The measurement > was done from RT up to the Curie temperature T_c of > the alloy. I want to compare my data to a Brillouin > function with different angular momenta J. Basically > I have to solve > > M/M_0=B_J[(T_c/T)(M/M_0)], > with > B_J=(2J+1/J)coth[(2J+1/2J)x]-(1/2J)coth[x/2J], > where > M_0 is the saturation magnetization > > How do I basically solve this and in parallel fit it > to my data? In principle I want to obtain M_0 and > T_c. My data consists of M(T). > > Thank you for your interest and answers, > Frank >