Pressure Induced Superconductivity and Multiple Structural Transitions in CsCl-Type Cubic CeZn Single Crystal

CsCl-type cubic compound CeZn exhibits a paramagnetic (PM) to antiferromagnetic (AFM) first-order transition at T-N similar to 30 K accompanied by a simultaneous structural transition from cubic to tetragonal structure as temperature decreases. Applying the pressure, the coupled magnetic and crystal structural transition becomes separated above 1.0 GPa and then the AFM order changes to ferromagnetic (FM). The FM ordering temperature decreases with further applying pressure and changes to a nonmagnetic state above similar to 3.0 GPa. In the nonmagnetic state, we discovered superconductivity below T-sc similar to 1.3 K over 5.5 GPa, which survives even up to 9.5 GPa. Investigation of single crystal X-ray diffraction at room temperature reveals that CeZn undergoes a sequential crystal structural change with increasing pressure from cubic at ambient pressure to the monoclinic structure at 8.2 GPa via tetragonal and orthorhombic structure. The detailed analysis of crystal structure in CeZn single crystal evidenced that the emergence of superconductivity is related to the orthorhombic-to-monoclinic transition implying a nonmagnetic origin of the Cooper pair formation.