Web based script which allows to fit specific heat of solids within Schotte-Schotte model.

Specific heat is fitted with function which consists of electronic contribution $\gamma T$, lattice contribution $ B T^3 $ and Schotte-Schotte term (Phys. Lett. 55, 1975, 38): $$ C=k \frac{2 S \Delta}{\pi k T} -2 k \Re{ \bigg\{ \frac{(\Delta+ \imath g \mu_B H)^2}{(2 \pi k T)^2} \Big( (2S+1)^2\psi^{'}(1+\frac{\Delta +\imath g \mu_B H}{ 2 \pi k T}(2S+1) \big) -\psi^{'} \big(1+\frac{\Delta +\imath g \mu_B H}{2 \pi k T} \big) \Big) \bigg\}} $$ where $\psi^{'}(z)$ is evaluated (according to Handbook of Contined Fractions for Special Functions, ISBN 978-I-4020-6948-2, pp 232): \[ \psi^{'}(z)=K_{m=0}^{\infty} \big(\frac{c_m z^{-1}}{1} \big),\quad \Re{z}>\frac{1}{2} \] with $$c_1=1,\quad c_{2j}=\frac{-j^2}{2(2j-1)},\quad c_{2j+1}=\frac{j^2}{2(2j+1)},\quad j\geq 1 $$



input xy data:
output xy data

scaling of Schotte-Schotte function A0 (x105): Fix
linear coefficient γ (J/molK2): Fix
cubic coefficient B (J/molK4): Fix
resonance width Δ (K): Fix
magnetic field H (T): Fix
spin: