THE INFLUENCE OF Sm3 IMPURITIES ON PROPERTIES OF PURE SmS AND ITS ALLOYS WITH LaSReportar como inadecuado




THE INFLUENCE OF Sm3 IMPURITIES ON PROPERTIES OF PURE SmS AND ITS ALLOYS WITH LaS - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.



Abstract : Compounds similar to SmS exhibit a number of unexplained anomalies. The resistivity of SmS and the alloys Sm1-xLaxS sohw a pronounced Kondo type resistivity minimum and in several cases a Log T behaviour at low temperature. This behaviour can not be intrinsic for the excited levels are too far in energy from the singlet ground state to be the origin of the magnetic resistivity. Recently the presence of Sm3+ has been detected by electron paramagnetic resonance in the temperature region where the Kondo effect is observed : between 1.2 and 20 K. The number of Sm3+, which are probably due to crystalline defects or vacancies, is estimated from the EPR to be between 0.5 and 5 %. Measurement of the specific heat in pure SmS and alloys with Y, between 1 and 4 K, have shown the presence of non-intrinsic effects. We have studied the magnetization to 150 kOe and 1.4 Kin the same samples as those used for the resistivity. The Sm3+ which have a small moment are saturated. At very low temperature, 70 mK, and 3 kOe field, the other impurities with a larger moment are saturated. Our measurements give the same order of magnitude for the Sm3+ concentration as the EPR measurements. We conclude that these compounds contain Sm3+. They are a new example of a rare earth impurity which causes a Kondo effect. Analysis of the specific heat results show that the Sm3+ anomaly is a single impurity effect and not an effect of interaction between impurities.





Autor: G. Chouteau O. Pena F. Holtzberg T. Penney R. Tournier S. Von Molnar

Fuente: https://hal.archives-ouvertes.fr/



DESCARGAR PDF




Documentos relacionados