Transition from itinerant to polaronic conduction in perovskites

R. Caciuffo; J. Mira; J. Rivas; M. A. Señarís-Rodríguez; P. G. Radaelli; F. Carsughi; D. Fiorani; J. B. Goodenough

doi:10.1209/epl/i1999-00178-y

All issues

Volume 45 / No 3 (February 1999)

Europhys. Lett., 45 3 (1999) 399-405

Abstract

Issue		Europhys. Lett. Volume 45, Number 3, February 1999


Page(s)		399 - 405
Section		Condensed matter: electronic structure, electrical, magnetic and optical properties
DOI		https://doi.org/10.1209/epl/i1999-00178-y
Published online		01 September 2002

Europhys. Lett., 45 (3), pp. 399-405 (1999)

Transition from itinerant to polaronic conduction in ${\rm La}_{1-x}{\rm Sr}_x{\rm CoO_3}$ perovskites

R. Caciuffo¹, J. Mira², J. Rivas², M. A. Señarís-Rodríguez³, P. G. Radaelli⁴, F. Carsughi¹^,5, D. Fiorani⁶ and J. B. Goodenough⁷

¹ Istituto Nazionale per la Fisica della Materia and Università di Ancona Via Brecce Bianche, 60131 Ancona, Italy
² Departamento de Física Aplicada, Universidade de Santiago E-15706 Santiago de Compostela, Spain
³ Departamento Quimica Fundamental e Industrial, Universidade da Coruña 15071 A Coruña, Spain
⁴ Rutherford Appleton Laboratory, ISIS Facility - Chilton, UK
⁵ Institut für Festkörperforschung des Forschungszentrum - 52425 Jülich, Germany
⁶ Istituto di Chimica dei Materiali, CNR - 00016 Monterotondo, Roma, Italy
⁷ Center for Materials Science and Engineering, University of Texas at Austin Texas 78712-1063, USA

Received: 11 September 1998
Accepted: 23 November 1998

Abstract

Neutron diffraction and small-angle scattering on ${\rm La}_{1-x}{\rm Sr}_x{\rm CoO}_3$ ( $0< x \le 0.30$ ) show that for x = 0.3 the system is near a two-phase percolation threshold and undergoes a transition from itinerant to polaronic conduction at the Curie temperature T_C. The stabilization of superparamagnetic clusters on warming through T_C is revealed by an anomalous thermal expansion of the volume and a deviation of the paramagnetic susceptibility from the Curie-Weiss law. The development of a temperature-dependent small-angle-scattering signal confirms that regions of short-range ferromagnetic order are present above $T_{\rm C}$ .

PACS: 75.25.+z – Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source X-ray scattering, etc.) / 72.15.-v – Electronic conduction in metals and alloys / 75.40.Cx – Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.)

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.