Magnetoresistance Effects in SrFeO(3-x): Dependence on Phase Composition and Relation to Magnetic and Charge Order

Abstract

Single crystals of iron(IV) rich oxides SrFeO(3-x) with controlled oxygen content have been studied by Moessbauer spectroscopy, magnetometry, magnetotransport measurements, Raman spectroscopy, and infrared ellipsometry in order to relate the large magnetoresistance (MR) effects in this system to phase composition, magnetic and charge order. It is shown that three different types of MR effects occur. In cubic SrFeO3 (x = 0) a large negative MR of 25% at 9 T is associated with a hitherto unknown 60 K magnetic transition and a subsequent drop in resistivity. The 60 K transition appears in addition to the onset of helical ordering at ~130 K. In crystals with vacancy-ordered tetragonal SrFeO(3-x) as majority phase (x ~0.15) a coincident charge/antiferromagnetic ordering transition near 70 K gives rise to a negative giant MR effect of 90% at 9 T. A positive MR effect is observed in tetragonal and orthorhombic materials with increased oxygen deficiency (x = 0.19, 0.23) which are insulating at low temperatures. Phase mixtures can result in a complex superposition of these different MR phenomena. The MR effects in SrFeO(3-x) differ from those in manganites as no ferromagnetic states are involved.

References in corpus (6)

• Infrared and Raman studies of the Verwey transition in magnetite
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• Magnetism, Charge Order and Giant Magnetoresistance in SrFeO${}_{3-\delta }$ Single Crystals
• Helicoidal ordering in iron perovskites
• Magnetization and magnetoresistance in insulating phases of SrFeO3-d
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Cited by in corpus (12)

• Versatile helimagnetic phases under magnetic fields in cubic perovskite SrFeO3
• Neutron diffraction study of spin and charge ordering in SrFeO(3-delta)
• Competing exchange interactions on the verge of a metal-insulator transition in the two-dimensional spiral magnet Sr${}_3$Fe${}_2$O${}_7$
• Pressure Induced Ferromagnetism in Cubic Perovskite SrFeO3 and BaFeO3
• Magnetic phase diagram of $S{r}_{3}F{e}_2{O}_{7-x}$
• Itinerancy-dependent non-collinear spin textures in SrFeO3, CaFeO3, and CaFeO3/SrFeO3 heterostructures probed via resonant x-ray scattering
• Antisite defects at oxide interfaces
• Floating Zone Growth of Large Single Crystals of SrFeO_3-x
• Spin-charge coupling and decoupling in perovskite-type iron oxides (Sr${}_{1-x}$Ba${}_x$)${}_{2/3}$La${}_{1/3}$FeO${}_3$
• Photoinduced Transient States of Antiferromagnetic Orderings in La${}_{1/3}$Sr${}_{2/3}$FeO${}_3$ and SrFeO${}_3$ Thin Films Observed through Time-resolved Resonant Soft X-ray Scattering
• Anomalous quasielastic scattering contribution in the centrosymmetric multi-$\mathbf{q}$ helimagnet SrFeO${}_3$
• Anisotropy in the thermal hysteresis of resistivity and charge density wave nature of single crystal SrFeO3-delta: X-ray absorption and photoemission studies