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Orbital domain state and finite size scaling in ferromagnetic insulating manganites

G. Papavassiliou·M. Belesi·M. Fardis·M. Pissas·J. Dolinsek·C. Dimitropoulos·J. P. Ansermet
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Abstract

55Mn and 139La NMR measurements on a high quality single crystal of ferromagnetic (FM) La0.80Ca20MnO3 demonstrate the formation of localized Mn(3+,4+) states below 70 K, accompanied with strong anomalous increase of certain FM neutron Bragg peaks. (55,139)(1/T1) spin-lattice relaxation rates diverge on approaching this temperature from below, signalling a genuine phase transition at T(tr) approx. 70 K. The increased local magnetic anisotropy of the low temperature phase, the cooling-rate dependence of the Bragg peaks, and the observed finite size scaling of T(tr) with Ca (hole) doping, are suggestive of freezing into an orbital domain state, precursor to a phase transition into an inhomogeneous orbitally ordered state embodying hole-rich walls.

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G. Papavassiliou, M. Belesi, M. Fardis, M. Pissas, J. Dolinsek, C. Dimitropoulos, J. P. Ansermet. 2002-10-21. Orbital domain state and finite size scaling in ferromagnetic insulating manganites. https://doi.org/10.1103/physrevlett.91.147205

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