N. Haldolaarachchige, J. Prestigiacomo, W. Adam Phelan, Y. M. Xiong, Greg McCandless, Julia Y. Chan, J. F. DiTusa, I. Vekhter, S. Stadler, D. E. Sheehy, P. W. Adams, D. P. Young
The magnetic, transport, and thermal properties of single crystals of the series Fe(Ga1-xGex)3 are reported. Pure FeGa3 is a nonmagnetic semiconductor, that when doped with small concentrations of Ge (extrinsic electrons), passes through an insulator-to-metal transition and displays non-Fermi liquid (NFL) behavior. Moreover, we observer clear signatures of a ferromagnetic quantum critical point (FM-QCP) in this system at x = 0.052. The mechanism of the local moment formation is consistent with a one-electron reduction of Fe dimer singlets, a unique structural feature in FeGa3, where the density of these mixed valence (Fe(III)-Fe(II)) dimers provides a unique tuning parameter of quantum criticality.
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http://arxiv.org/abs/1304.1897
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