Possible quantum critical point in La(2/3)Ca(1/3)Mn(1-x)Ga x O3.
We study the magnetic ground state in La(2/3)Ca(1/3)Mn(1-x)Ga x O3 manganites, where a quantum critical point (QCP) has been theoretically predicted. The metallic ferromagnetic ground state for low Ga doping breaks down for x > or = 0.11, an insulating state being established at low temperatures. Long-range ferromagnetism coexists with short-range magnetic correlations in the concentration range 0.11 < or = x < or = 0.145 while only the short-range correlations survive for x > or = 0.16. We discuss the implications of such a QCP to the physics of manganites and compare to other QCP systems.
De Teresa
J M
JM
Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-CSIC, Zaragoza, Spain. deteresa@unizar.es
Algarabel
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Ritter
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Blasco
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Ibarra
M R
MR
Morellon
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Espeso
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Gómez-Sal
J C
JC