文摘
We have investigated the evolution of magnetic properties in pseudo-ternary UCo1−xPdxGe (x=0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9) intermetallics by measurements of ac-magnetic susceptibility and dc-magnetization. The measured samples have been prepared by arc-melting and characterized by powder X-ray diffraction and X-ray energy-dispersive electron spectroscopy technique. Rietveld refinements of the X-ray patterns indicate that the pseudo-ternaries crystallize in the orthorhombic TiNiSi-type structure with Pnma space group as the parent UCoGe and UPdGe compounds do. The magnetic measurements reveal that in addition to an increase in 5f -electron localization degree with increasing Pd concentration, an interesting magnetic phase diagram, which is more complex than that expected from the gradual change in magnetic ground state due to the substitution. Three compositional ranges with different magnetic properties have been established; the coexistence of spin-glass and itinerant-electron ferromagnetic orderings for thmlsrc">text stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022459616302857&_mathId=si0015.gif&_user=111111111&_pii=S0022459616302857&_rdoc=1&_issn=00224596&md5=8d660925e6bd486a9d50b84ad07970ce" title="Click to view the MathML source">x≤0.3thContainer hidden">thCode">th altimg="si0015.gif" overflow="scroll">x≤0.3th>, antiferromagnetic order occurs in the range thmlsrc">text stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022459616302857&_mathId=si0016.gif&_user=111111111&_pii=S0022459616302857&_rdoc=1&_issn=00224596&md5=9b1f3eb60d930d0da911107142d5fa4c" title="Click to view the MathML source">0.4≤x≤0.7thContainer hidden">thCode">th altimg="si0016.gif" overflow="scroll">0.4≤x≤0.7th>, and a complex ferromagnetic structure of more localized 5f moments takes place in thmlsrc">text stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022459616302857&_mathId=si0017.gif&_user=111111111&_pii=S0022459616302857&_rdoc=1&_issn=00224596&md5=f4339768d13a60c12ff3599ef04f37a0" title="Click to view the MathML source">x≥0.8thContainer hidden">thCode">th altimg="si0017.gif" overflow="scroll">x≥0.8th>. The evolution of magnetic ground states in UCo1−xPdxGe is discussed in terms of interplay between cooperative magnetic interactions. We consider also implications of increasing conduction electrons upon the Pd substitution in Ruderman-Kittel-Kasuya-Yosida interactions, which would give rise to the evolution of magnetic properties in UCo1−xPdxGe pseudo-ternaries.