Magnetic and superconducting transitions in GdxEr1−xRb4B4 and GdxY1−xRh4B4

Abstract

The magnetic and superconducting transition temperatures and upper critical fields have been measured for Gd_xEr_1−xRh₄B₄ and Gd_xY_1−xRh₄B₄. The pressure dependence of T_c for the Er system for x?0.05 is 0.5×10⁻² K/kbar. Both systems exhibit reentrant behavior, that is a superconducting transition followed by a magnetic transition at a lower temperature that destroys the superconductivity. For the Er system, the initial additions of Gd actually raise the superconducting critical field followed by the expected decrease for greater additions.