Correlation between phase competition and the nucleation of a Griffiths-like phase in (La1-yPry)0.7Ca0.3Mn16/18O3Wanjun Jiang, XueZhi Zhou and Gwyn Williams
Department of Physics and Astronomy, University of Manitoba - Winnipeg, Manitoba, R3T 2N2 Canada
received 24 July 2008; accepted in final form 20 October 2008; published November 2008
published online 21 November 2008
Detailed analyses of the temperature-dependent zero-field ac susceptibility of prototypical phase-separated (La1-yPry)0.7Ca0.3Mn16/18O3 , 0 y 1, reveal features consistent with the presence of a Griffiths-like phase (GP), viz, an inverse susceptibility characterized by with as y decreases towards 0.85. Beyond = 0.85, the GP is suppressed. These data, combined with previous neutron diffraction measurements, enable a phase diagram summarizing the evolution of the GP with composition to be constructed for this system; this phase diagram demonstrates the novel result that the disorder relevant for the establishment of such a phase in this system is linked closely to the relative volume fractions of the phase-separated antiferromagnetic and ferromagnetic components, even when the recently estimated double-exchangelinked percolation threshold is exceeded. The influence of electron-phonon coupling can also be seen through oxygen isotope effects.
75.40.Cx - Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.).
75.47.Lx - Manganites.
75.47.Gk - Colossal magnetoresistance.
© EPLA 2008