title: Critical phenomena and the quantum critical point of ferromagnetic Zr(1-x)NbxZn2.
abstract: We present a study of the magnetic properties of Zr(1-x)NbxZn2, using an Arrott plot analysis of the magnetization. The Curie temperature Tc is suppressed to zero temperature for Nb concentration xc = 0.083+/-0.002, while the spontaneous moment vanishes linearly with Tc as predicted by the Stoner theory. The initial susceptibility chi displays critical behavior for x <or= xc , with a critical exponent which smoothly crosses over from the mean field to the quantum critical value. For high temperatures and x <or= xc, and for low temperatures and x >or= xc we find that chi(-1) = chi0(-1) + aT(4/3), where chi0(-1) vanishes as x-->xc. The resulting magnetic phase diagram shows that the quantum critical behavior extends over the widest range of temperatures for x=xc, and demonstrates how a finite transition temperature ferromagnet is transformed into a paramagnet, via a quantum critical point.
authors.affiliation: University of Michigan, Ann Arbor, Michigan 48109-1120, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Sokolov
authors.forename: M C
authors.initials: MC
authors.lastname: Aronson
authors.forename: W
authors.initials: W
authors.lastname: Gannon
authors.forename: Z
authors.initials: Z
authors.lastname: Fisk