MCD Study on Materials without Magnetic Order

Abstract

Core excited magnetic circular dichroism (MCD) signals have been measured on PrFe₄P₁₂ and CePd₃ under the states without magnetic order. The inverse values of the MCD magnitudes have been plotted against temperatures to be compared with the inverse plots of the bulk susceptibility. It has been found on PrFe₄P₁₂ that the inverse of MCD magnitudes behaves like a material with local magnetic moments at high temperature region but behaves as if the local magnetic moments disappear at low temperature region with T_K much higher than 10 K, while its bulk susceptibility is known to show a “ferromagnetic” behavior above 6 K. Those on CePd₃ have been found to behave like a normal dilute Kondo alloy as if T_K is around 20 K, which contradicts the known T_K of 150 K and is in striking contrast to our former result on CeFe₄P₁₂. This result suggests that T_K of a “coherent” Kondo material could be much higher than T_K observed through “local” spin fluctuation due to some antiferromagnetic interaction between neighboring 4f moments.