Unformatted text preview:
View Full Document
MIT OpenCourseWare http ocw mit edu 8 512 Theory of Solids II Spring 2009 For information about citing these materials or our Terms of Use visit http ocw mit edu terms 1 8 512 Theory of Solids II Problem Set 10 Due April 29 2009 1 a Using linear response theory derive the following expression for the magnetic susceptibility Mz Hz 1 e kT d hSz q Sz q i q 0 2 b Provided that the total magnetization Mz i Siz commutes with the Hamil lim tonian we can start from the expression F kT ln T r e H Mz Hz and take derivatives with respect to Hz to derive the simpler expression 1 hMz2 i kT Show that this is consistent with the more general expression obtained in 2 a Hint in this special case limq 0 h Sz q 2 i
View Full Document
Unlocking...