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Colossal Magnetoresistance by Avoiding a Ferromagnetic State in the Mott System Ca3Ru2O7

X. N. Lin·Z. X. Zhou·V. Durairaj·P. Schlottmann·G. Cao
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Abstract

Transport and magnetic studies of Ca3Ru2O7 for temperatures ranging from 0.4 K to 56 K and magnetic fields, B, up to 45 T leads to strikingly different behavior when the field is applied along the different crystal axes. A ferromagnetic (FM) state with full spin polarization is achieved for B||a-axis, but colossal magnetoresistance is realized only for B||b-axis. For B||c-axis, Shubnikov-de Haas oscillations are observed and followed by a less resistive state than for B||a. Hence, in contrast to standard colossal magnetoresistive materials, the FM phase is the least favorable for electron hopping. These properties together with highly unusual spin-charge-lattice coupling near the Mott transition (48 K) are driven by the orbital degrees of freedom.

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X. N. Lin, Z. X. Zhou, V. Durairaj, P. Schlottmann, G. Cao. 2005-03-30. Colossal Magnetoresistance by Avoiding a Ferromagnetic State in the Mott System Ca3Ru2O7. https://doi.org/10.1103/physrevlett.95.017203

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