Abstract
Layered cobalt oxides RBaCo2O5+x (R is a rare-earth element) possess very rich phase diagrams owing to the competition of various spin-charge-orbital ordered states in the doped square-lattice CoO2 planes. To clarify the mechanism of the giant magnetoresistance (GMR) that accompanies magnetic transformations in these compounds we have prepared and studied GdBaCo2O5+x single crystals with precisely tuned doping levels. We .nd that the GMR is observed even in the parent composition (x = 0.50) with all cobalt ions in the Co3+ state, which has neither phase segregation nor charge ordering that are responsible for the MR in manganites. A new MR mechanism is suggested for these cobalt oxides where the charge carrier generation in conducting channels is controlled by the magnetic state of their local environment.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Dagotto, E., Hotta, T., and Moreo, A. (2001) Colossal magnetoresistant materials: the key role of phase separation, Phys. Rep. 344, 1–153.
Frontera, C., GarcÃa-Muñoz, J. L., Llobet, A., and Aranda, M. A. G. (2002) Selective spinstate switch and metal-insulator transition in GdBaCo2O5.5, Phys. Rev. B 65, 180405-1–180405-4.
Kimura, T., Tomioka, Y., Kuwahara, H., Asamitsu, A., Tamura, M., and Tokura, Y. (1996) Interplane Tunneling Magnetoresistance in a Layered Manganite Crystal, Science 274, 1698–1701.
Martin, C., Maignan, A., Pelloquin, D., Nguyen, N., and Raveau, B. (1997) Magnetoresistance in the oxygen deficient LnBaCo2O5.4 (Ln = Eu, Gd) phases, Appl. Phys. Lett. 71, 1421–1423.
Nagaev, E. L. (1996) Lanthanum manganites and other giant-magnetoresistance magnetic conductors, Phys. Usp. 39, 781–805.
Respaud, M., Frontera, C., GarcÃa-Muñoz, J. L., Aranda, M. A. G., Raquet, B., Broto, J. M., Rakoto, H., Goiran, M., Llobet, A., and RodrÃguez-Carvajal, J. (2001) Magnetic and magnetotransport properties of GdBaCo2O5+δ: A high magnetic-field study, Phys. Rev. B 64, 214401-1–214401-7.
Taskin, A. A., Lavrov, A. N., and Ando, Y. (2003) Ising-Like Spin Anisotropy and Competing Antiferromagnetic-Ferromagnetic Orders in GdBaCo2O5.5 Single Crystals, Phys. Rev. Lett. 90, 227201-1–227201-4.
Taskin, A. A., Lavrov, A. N., and Ando, Y. (2005) Transport and magnetic properties of GdBaCo2O5+x single crystals: A cobalt oxide with square-lattice CoO2 planes over a wide range of electron and hole doping, Phys. Rev. B 71, 134414-1–134414-28.
Tomioka, Y., Asamitsu, A., Moritomo, Y., Kuwahara, H., and Tokura, Y. (1995) Collapse of a Charge-Ordered State under a Magnetic Field in Pr1/2Sr1/2MnO3, Phys. Rev. Lett. 74, 5108–5111.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2007 Springer
About this paper
Cite this paper
Lavrov, A.N., Taskin, A.A., Ando, Y. (2007). SPIN-ORBITAL ORDERING AND GIANT MAGNETORESISTANCE IN COBALT OXIDES: INTRINSIC MAGNETIC-FIELD-EFFECT TRANSISTOR. In: Scharnberg, K., Kruchinin, S. (eds) Electron Correlation in New Materials and Nanosystems. NATO Science Series, vol 241. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-5659-8_30
Download citation
DOI: https://doi.org/10.1007/978-1-4020-5659-8_30
Publisher Name: Springer, Dordrecht
Print ISBN: 978-1-4020-5657-4
Online ISBN: 978-1-4020-5659-8
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)