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arXiv · 1204.0083

Korringa-like relaxation in the high-temperature phase of A-site ordered YBaMn2O6

S. Schaile·H. -A. Krug von Nidda·J. Deisenhofer·A. Loidl·T. Nakajima·Y. Ueda
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Abstract

We report on high-temperature electron spin resonance studies of A-site ordered YBaMn2O6 and disordered Y0.5Ba0.5MnO3. In the disordered sample we find that the linewidth is governed by spin-spin relaxation processes as in many other manganite systems. In contrast we find a Korringa-like spin relaxation with a slope of about 1 Oe/K above the charge-ordering transition and extending up to 930K in the metal ordered YBaMn2O6 samples. A Korringa-law is a clear feature of a truly metallic state, pointing to an unconventional high-temperature phase of these ordered manganites. In agreement with the ESR intensity this suggests that in the metallic high-temperature phase the ESR signal stems from Mn^4+ core spins which relax via the quasi-delocalized e_g electrons.

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S. Schaile, H. -A. Krug von Nidda, J. Deisenhofer, A. Loidl, T. Nakajima, Y. Ueda. 2012-03-31. Korringa-like relaxation in the high-temperature phase of A-site ordered YBaMn2O6. https://doi.org/10.1103/physrevb.85.205121

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