Anisotropy of electric resistance and upper critical field in magnetic superconductor Dy$_{0.6}$Y$_{0.4}$Rh$_{3.85}$Ru$_{0.15}$B$_4

• Main Authors: Terekhov, A. V, Zolochevskii, I. V, Khristenko, E. V, Ishchenko, L. A, Bezuglyi, E. V, Zaleski, A, Khlybov, E. P, Lachenkov, S. A
• Format: Journal Article
• Language: English
• Published: 12-07-2015
• Subjects: Physics - Superconductivity
• DOI: 10.48550/arxiv.1507.03247

We have measured temperature dependencies of the electric resistance $R$ and
upper critical magnetic field $H_{c2}$ of a magnetic superconductor
Dy$_{0.6}$Y$_{0.4}$Rh$_{3.85}$Ru$_{0.15}$B$_4$. The measurements were made for
different angles $\varphi$ of magnetic field inclination to the direction of
measuring current and revealed strong anisotropy of the behavior of $R(T)$ and
the values of $H_{c2}(T)$. By using the Werthamer-Gelfand-Hohenberg theory, we
determined the Maki parameter $\alpha$ and the parameter of the spin-orbital
interaction. For $\varphi = 0^\circ$ and $90^\circ$ both parameters are close
to zero, thus the magnitude of $H_{c2}(0) \approx 38$ kOe is basically limited
by the orbital effect. At $\varphi = 45^\circ$, a large value of the parameter
$\alpha = 4.2$ indicates dominating role of the spin-paramagnetic effect in the
suppression of $H_{c2}(0)$ down to $8.8$ kOe. We suggest that such behavior of
$R(T)$ and $H_{c2}(T)$ is caused by internal magnetism of the Dy atoms which
may strongly depend on the magnetic field orientation.