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Itinerant Ferromagnetism and Metamagnetism in Cr Doped Perovskite Ruthenates

V. Durairaj·E. Elhami·S. Chikara·X. N. Lin·A. Douglass·G. Cao P. Schlottmann·E. S. Choi·R. P. Guertin
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Abstract

We report results of structural, magnetic and transport properties of single crystal CaRu1-xCrxO3 (0≤x≤0.36) and SrRu1-xCrxO3 (0≤x≤0.30). Cr substitution as low as x=0.08 drives CaRu1-xCrxO3 from the paramagnetic state to an itinerant ferromagnetic state with field-driven first-order metamagnetic transitions leading to a sizeable saturation moment (~0.4B/f.u.within the ab plane). The ferromagnetism occurs abruptly and reaches as high as TC=123 K for x=0.22. The Cr-driven ferromagnetism is highly anisotropic, suggesting an important role for spin-orbit coupling. Lattice constant and magnetic measurements strongly support the valence of the Cr as tetravalent (Cr4+, 3d2 configuration). Cr substitution for Ru in SrRuO3 (TC=165 K) enhances the itinerant ferromagnetism, with TC reaching 290 K for x=0.30, consistent with Cr-induced ferromagnetism in paramagnetic CaRuO3. Preliminary pressure-dependent magnetization of CaRu0.85Cr0.15O3 shows strong enhancement of the saturation magnetization (25% for P~0.7 GPa). All results indicate a coupling of Ru 4d and Cr 3d electrons that is unexpectedly favorable for itinerant ferromagnetism which often exists delicately in the ruthenates.

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V. Durairaj, E. Elhami, S. Chikara, X. N. Lin, A. Douglass, G. Cao P. Schlottmann, E. S. Choi, R. P. Guertin. 2005-09-04. Itinerant Ferromagnetism and Metamagnetism in Cr Doped Perovskite Ruthenates. https://arxiv.org/abs/cond-mat/0509084

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