Magnetic Susceptibility of a Dirty BEC System Ni$_{0.85}$Cd$_{0.15}$-4SC(NH$_{2})_{2}$

We report measurements of the magnetic susceptibility of a dirty BEC system of magnons: Ni$_{0.85}$Cd$_{0.15}$-4SC(NH$_{2})_{2}$ (The 15{\%}Cd site-diluted DTN) was studied down to 10 mK. Below 100 mK, the critical fields of BEC $H_{c}$ do not obey the conventional 3D universality class $H_{c}(T)$ -- $H_{c}(0) \quad \sim \quad T^{\alpha }$, where $\alpha $ = 1.5. The observed scaling relation of $\alpha $ = 1/1.15 below 100 mK is in agreement with the numerical simulation of Bose glass for this system.