Superconductivity, magnetic order, and quadrupolar order in the filled skutterudite system Pr${}_{1-x}$Nd${}_x$Os${}_4$Sb${}_{12}$

Abstract

Superconductivity, magnetic order, and quadrupolar order have been investigated in the filled skutterudite system Pr${}_{1-x}$Nd${}_x$Os${}_4$Sb${}_{12}$ as a function of composition $x$ in magnetic fields up to 9 tesla and at temperatures between 50 mK and 10 K. Electrical resistivity measurements indicate that the high field ordered phase (HFOP), which has been identified with antiferroquadruoplar order, persists to $x$ $\sim$ 0.5. The superconducting critical temperature $T_c$ of PrOs${}_4$Sb${}_{12}$ is depressed linearly with Nd concentration to $x$ $\sim$ 0.55, whereas the Curie temperature $T_{FM}$ of NdOs${}_4$Sb${}_{12}$ is depressed linearly with Pr composition to ($1-x$) $\sim$ 0.45. In the superconducting region, the upper critical field $H_{c2}(x,0)$ is depressed quadratically with $x$ in the range 0 $<$ $x$ $\lesssim$ 0.3, exhibits a kink at $x$ $\approx$ 0.3, and then decreases linearly with $x$ in the range 0.3 $\lesssim$ $x$ $\lesssim$ 0.6. The behavior of $H_{c2}(x,0)$ appears to be due to pair breaking caused by the applied magnetic field and the exhange field associated with the polarization of the Nd magnetic moments, in the superconducting state. From magnetic susceptibility measurements, the correlations between the Nd moments in the superconducting state appear to change from ferromagnetic in the range 0.3 $\lesssim$ $x$ $\lesssim$ 0.6 to antiferromagnetic in the range 0 $<$ $x$ $\lesssim$ 0.3. Specific heat measurements on a sample with $x$ $=$ 0.45 indicate that magnetic order occurs in the superconducting state, as is also inferred from the depression of $H_{c2}(x,0)$ with $x$.

7 pages, 7 figures, currently submitted to Phys. Rev. B

References in corpus (8)

• Time-Reversal Symmetry-Breaking Superconductivity in Heavy Fermion PrOs4Sb12 detected by Muon Spin Relaxation
• The Crystal Field Potential of PrOs4Sb12: Consequences for Superconductivity
• Multiband superconductivity in the heavy fermion compound PrOs4Sb12
• Probing the superconducting gap symmetry of PrOs${}_4$Sb${}_{12}$: A penetration depth study
• Superconducting phase diagram of the filled skuterrudite PrOs4Sb12
• Ferromagnetism and possible heavy fermion behavior in single crystals of NdOs${}_4$Sb${}_{12}$
• High magnetic field phase diagram of PrOs4Sb12
• Double superconducting transition in the filled skutterudite PrOs4Sb12 and sample characterizations

Cited by in corpus (2)

• Muon spin rotation and relaxation in Pr${}_{1-x}$Nd${}_x$Os${}_4$Sb${}_{12}$: Magnetic and superconducting ground states
• Muon spin rotation and relaxation in Pr${}_{1-x}$Nd${}_x$Os${}_4$Sb${}_{12}$: Paramagnetic states