Ferromagnetic quantum critical point induced by dimer-breaking in SrCo{sub 2}(Ge{sub 1-x}P{sub x}){sub 2}.

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Nat. Phys.

DOI:https://doi.org/10.1038/nphys1868· OSTI ID:1010909

Jia, S; Jiramongkolchai, P; Suchomel, M R; Toby, B H; Checkelsky, J G; Ong, N P; Cava, R J ^[1]

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1. X-Ray Science Division

In contrast to classical phase transitions driven by temperature, a quantum critical point (QCP) defines a transition at zero temperature that is driven by non-thermal parameters. In the known quantum critical d-electron systems, tuning the electronic bandwidth by means of changing the applied pressure or unit-cell dimensions, or tuning the d-state population, is used to drive the criticality. Here we describe how a novel chemical parameter, the breaking of bonds in Ge-Ge dimers that occurs within the intermetallic framework in SrCo{sub 2}(Ge{sub 1-x}P{sub x}){sub 2}, results in the appearance of a ferromagnetic (FM) QCP. Although both SrCo{sub 2}P{sub 2} and SrCo{sub 2}Ge{sub 2} are paramagnetic, weak itinerant ferromagnetism unexpectedly develops during the course of the dimer breaking, and a QCP is observed at the onset of the FM phase. The use of chemical bond breaking as a tuning parameter to induce QCP opens an avenue for designing and studying novel magnetic materials.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1010909
• Report Number(s): ANL/XSD/JA-69629
• Journal Information: Nat. Phys., Journal Name: Nat. Phys. Journal Issue: 2011 Vol. 7; ISSN 1745-2473
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHEMICAL BONDS
CRITICALITY
DIMENSIONS
DIMERS
FERROMAGNETISM
MAGNETIC MATERIALS
TUNING