Curie Temperatures of Substituted Rare Earth-Aluminium L1-xRxAl2 Compounds

J. Pszczoła Department of Experimental Physics, Faculty of Mathematics and Applied Physics, Rzeszów University of Technology, al. Powstańców Warszawy 6, 35-959 Rzeszów, Poland

Full Text PDF

The experimental Curie temperatures of the substituted rare earth-aluminium L1-xRxAl2 compounds (with rare earths L, R: La, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Y) scale linearly with the de Gennes factor. The magnetic rare-earth sublattice is treated as being composed of two magnetic subsystems: the 4f subsystem of L3+ or R3+ ions and the 5d subsystem of band electrons. The de Gennes factor G=(g-1)2J(J+1), with g as the Landé factor and J as the total angular momentum quantum number, reflects the 4f shell quantum properties of the L3+ or R3+ ion. A formula introducing the linear dependence of the Curie temperature on the de Gennes factor for the substituted rare earth-aluminium compounds is derived with consideration of the Zener-type 4f-5d exchange interaction within the frame of the molecular field model. The obtained formula was tested for a number of different members of the heavy rare earth-aluminium intermetallic series. A relative constancy of the 4f-5d exchange interaction across the considered L1-xRxAl2 series has been deduced. The formula can easily be adapted also to describe the non-linear dependences of the Curie temperatures on the de Gennes factor.

DOI:10.12693/APhysPolA.140.72 topics: substituted intermetallics, rare earth-aluminium, Curie temperature formula, linear dependence