Anisotropic $H_{c2}$ curves determined up to 92 T and the signature of two-band superconductivity in the novel superconductor Ca$_{10}$(Pt$_{4}$As$_{8})$((Fe$_{1-x}$Pt$_{x})_{2}$As$_{2})_{5}$

The upper critical fields, $H_{c2}(T)$, of single crystals of the novel superconductor Ca$_{10}$(Pt$_{4}$As$_{8})$((Fe$_{1-x}$Pt$_{x})_{2}$As$_{2})_{5}$ with $x$=0.02 were determined over a wide range of temperatures down to $T$ = 1.42 K and magnetic fields up to $H $= 92 T. The measurements of anisotropic $H_{c2}(T)$ curves are performed in pulsed magnetic fields using radio-frequency contactless penetration depth measurements for magnetic field applied both parallel and perpendicular to the ab-plane. Whereas a clear upward curvature in $H_{c2}^{c}(T)$ along H$\vert \vert $c is observed with decreasing temperature, the $H_{c2}^{ab}(T)$ along H$\vert \vert $ab shows a flattening at low temperatures. The rapid increase of the $H_{c2}^{c}(T)$ suggests that the superconductivity can be described by two dominating bands. The anisotropy parameter, $H_{c2}^{ab}(T)$ /$ H_{c2}^{c}(T)$ , is $\sim $7 close to $T_{c}$ and decreases considerably to $\sim $1 with decreasing temperature, showing rather weak anisotropy at low temperatures.