Correlation between phase competition and the nucleation of a Griffiths-like phase in (LaPry)0.7Ca0.3Mn16/18O3

Wanjun Jiang; XueZhi Zhou; Gwyn Williams

doi:10.1209/0295-5075/84/47009

All issues

Volume 84 / No 4 (November 2008)

EPL, 84 4 (2008) 47009

Abstract

Issue		EPL Volume 84, Number 4, November 2008


Article Number		47009
Number of page(s)		6
Section		Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI		https://doi.org/10.1209/0295-5075/84/47009
Published online		21 November 2008

EPL, 84 (2008) 47009

Correlation between phase competition and the nucleation of a Griffiths-like phase in (La $_{1-y}$ Pr_y)_0.7Ca_0.3Mn^16/18O₃

Wanjun Jiang, XueZhi Zhou and Gwyn Williams

Department of Physics and Astronomy, University of Manitoba - Winnipeg, Manitoba, R3T 2N2 Canada

Corresponding author: jiang@physics.umanitoba.ca

Received: 24 July 2008
Accepted: 20 October 2008

Abstract

Detailed analyses of the temperature-dependent zero-field ac susceptibility of prototypical phase-separated (La $_{1-y}$ Pr_y)_0.7Ca_0.3Mn^16/18O₃ , 0 $\leqslant$ y $\leqslant$ 1, reveal features consistent with the presence of a Griffiths-like phase (GP), viz, an inverse susceptibility $(\chi ^{-1})$ characterized by $\chi ^{-1}\propto (T-T_{{\rm C}}^{{\rm Rand}})^{1-\lambda}$ with $0.05\leqslant \lambda \leqslant 0.33$ as y decreases towards $y_{{\rm c}}$ $\leqslant$ 0.85. Beyond $y_{{\rm c}}$ = 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-exchange $\hbox{--}$ linked percolation threshold is exceeded. The influence of electron-phonon coupling can also be seen through oxygen isotope effects.

PACS: 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

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