Electron concentration effects on the Shastry-Sutherland phase stability in Ce_{2-x}Pd_{2+y}In_{1-z} solid solutions

摘要

The stability of a Shastry-Sutherland ShSu phase as a function of electronconcentration is investigated through the field dependence of thermal andmagnetic properties of the solid solution Ce_{2-x}Pd_{2+y}In_{1-z} in theantiferromagnetic branch. In these alloys the electronic (holes) variation isrealized by increasing $Pd$ concentration. The AF transition T_M decreases from3.5K to 2.8K as $Pd$ concentration increases from y=0.2 to y=0.4. By applyingmagnetic field, the ShSu phase is suppressed once the field inducedferromagnetic polarization takes over at a critical field B_{cr} whichincreases with $Pd$ content. A detailed analysis around the critical pointreveals a structure in the maximum of the dM/dB derivative, which is relatedwith incipient steps in the magnetization M(B) as predicted by the theory forthe ShSu lattice. The crossing of M(B) isotherms, observed in ShSu prototypecompounds, is also analyzed. The effect of $In$ substitution by $Pd$ isinterpreted as an increase of the number of 'holes' in the conduction band andresults in a unique parameter able to describe the variation of the magneticproperties along the studied range of concentration.