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

Abstract

The stability of a Shastry-Sutherland ShSu phase as a function of electron concentration is investigated through the field dependence of thermal and magnetic properties of the solid solution Ce_{2-x}Pd_{2+y}In_{1-z} in the antiferromagnetic branch. In these alloys the electronic (holes) variation is realized by increasing $Pd$ concentration. The AF transition T_M decreases from 3.5K to 2.8K as $Pd$ concentration increases from y=0.2 to y=0.4. By applying magnetic field, the ShSu phase is suppressed once the field induced ferromagnetic polarization takes over at a critical field B_{cr} which increases with $Pd$ content. A detailed analysis around the critical point reveals a structure in the maximum of the dM/dB derivative, which is related with incipient steps in the magnetization M(B) as predicted by the theory for the ShSu lattice. The crossing of M(B) isotherms, observed in ShSu prototype compounds, is also analyzed. The effect of $In$ substitution by $Pd$ is interpreted as an increase of the number of 'holes' in the conduction band and results in a unique parameter able to describe the variation of the magnetic properties along the studied range of concentration.