Abstract
Comprehensive magnetic-field-orientation dependent studies of the susceptibility and de Haas–van Alphen effect have been carried out on single crystals of the filled skutterudites PrOs4As12 and LaOs4As12 using magnetic fields of up to 40 T. Several peaks are observed in the low-field susceptibility of PrOs4As12, corresponding to cascades of metamagnetic transitions separating the low-field antiferromagnetic and high-field paramagnetic metal (PMM) phases. The de Haas–van Alphen experiments show that the Fermi-surface topologies of PrOs4As12 in its PMM phase and LaOs4As12 are very similar. In addition, they are in reasonable agreement with the predictions of bandstructure calculations for LaOs4As12 on the PrOs4As12 lattice. Both observations suggest that the Pr 4f electrons contribute little to the number of itinerant quasiparticles in the PMM phase. However, while the properties of LaOs4As12 suggest a conventional nonmagnetic Fermi liquid, the effects of direct exchange and electron correlations are detected in the PMM phase of PrOs4As12. For example, the quasiparticle effective masses in PrOs4As12 are found to decrease with increasing field, probably reflecting the gradual suppression of magnetic fluctuations associated with proximity to the low-temperature, low-field antiferromagnetic state.
Highlights
Experimental details and bandstructure calculationsSingle crystals of PrOs4As12 and LaOs4As12 were grown from elements with purities 99.9% using the high-temperature molten-metal-flux procedure described in [12]
Our susceptibility measurements show that the antiferromagnetic to paramagnetic metal (PMM) transition in PrOs4As12 proceeds via 3 or 4 metamagnetic transitions, the field positions of which depend strongly on the orientation of the crystal in the field
The de Haas–van Alphen experiments demonstrate that the Fermi-surface topologies of PrOs4As12 in its PMM phase and LaOs4As12 are rather similar
Summary
Single crystals of PrOs4As12 and LaOs4As12 were grown from elements with purities 99.9% using the high-temperature molten-metal-flux procedure described in [12]. The torque magnetometer is mounted on a two-axis cryogenic goniometer that allows the sample orientation to be changed in situ; 3He refrigeration provides temperatures in the range 0.45–10 K. Fine-tuning of the compensation is accomplished by electronically adding or subtracting a small part of the voltage induced in a coaxial single-turn coil wound around the susceptometer [15]. Once this has been done, the signal from the susceptometer is V ∝ (dM/dt) = (dM/dH )(dH/dt), where M is the magnetization of a sample placed within the bore of the coil and H is the applied magnetic field [15]. Magnetic fields were deduced by integrating the voltage induced in an
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
