Maple M B, Butch N P, Frederick N A, Ho P-C, Jeffries J R, Sayles T A, Yanagisawa T, Yuhasz W M, Chi Songxue, Kang H J, Lynn J W, Dai Pengcheng, McCall S K, McElfresh M W, Fluss M J, Henkie Z, Pietraszko A
Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA.
Proc Natl Acad Sci U S A. 2006 May 2;103(18):6783-9. doi: 10.1073/pnas.0601541103. Epub 2006 Apr 21.
Electrical resistivity, specific heat, and magnetization measurements to temperatures as low as 80 mK and magnetic fields up to 16 T were made on the filled skutterudite compound PrOs4As12. The measurements reveal the presence of two ordered phases at temperatures below approximately 2.3 K and in fields below approximately 3 T. Neutron-scattering experiments in zero field establish an antiferromagnetic ground state < 2.28 K. In the antiferromagnetically ordered state, the electronic-specific heat coefficient gamma approximately 1 J/mol x K2 below 1.6 K and 0 < or = H < or = 1.25 T. The temperature and magnetic-field dependence of the electrical resistivity and specific heat in the paramagnetic state are consistent with single-ion Kondo behavior with a low Kondo temperature on the order of 1 K. The electronic-specific heat in the paramagnetic state can be described by the resonance-level model with a large zero-temperature electronic-specific heat coefficient that decreases with increasing magnetic field from approximately 1 J/mol x K2 at 3 T to approximately 0.2 J/mol x K2 at 16 T.
对填充式方钴矿化合物PrOs4As12进行了电阻率、比热和磁化强度测量，测量温度低至80 mK，磁场高达16 T。测量结果表明，在温度低于约2.3 K和磁场低于约3 T时存在两个有序相。零场下的中子散射实验确定了低于2.28 K的反铁磁基态。在反铁磁有序状态下，电子比热系数γ在1.6 K以下且0≤H≤1.25 T时约为1 J/mol·K²。顺磁状态下电阻率和比热的温度及磁场依赖性与低近藤温度（约为1 K）的单离子近藤行为一致。顺磁状态下的电子比热可用共振能级模型描述，该模型具有大的零温电子比热系数，其随磁场增加从3 T时的约1 J/mol·K²降至16 T时的约0.2 J/mol·K²。
