eprintid: 1280
rev_number: 9
eprint_status: archive
userid: 5
dir: disk0/00/00/12/80
datestamp: 2015-11-07 13:19:20
lastmod: 2015-11-09 05:56:56
status_changed: 2015-11-07 13:19:20
type: article
metadata_visibility: show
creators_name: Tran, Dang Thanh
creators_name: Phan, T. L
creators_name: Phung, Quoc Thanh
creators_name: Hoang, Nam-Nhat
creators_name: Duong, Anh Tuan
creators_name: Yu, S. C
creators_id: nhathn@vnu.edu.vn
title: Electrical and Magnetotransport Properties of La0.7Ca0.3Mn1−xCoxO3
ispublished: pub
subjects: Phys
divisions: fac_physic
abstract: This paper presents a detailed study on the Co-doping influence on the electrical and magnetotransport properties of La0.7Ca0.3Mn1-xCoxO3(x = 0.09-0.17) prepared by solid-state reaction. Magnetic measurements versus temperature revealed a gradual decrease of the magnetization (M) and Curie temperature (T-C) with increasing Co concentration (x). The T-C values vary from 194 to 159 K as changing x from 0.09 to 0.17, respectively. H/M versus M-2 performances around T-C prove the x = 0.09 sample undergoing a first-order magnetic phase transition (FOMT) while the samples with x >= 0.11 undergo a second-order magnetic phase transition (SOMT). The other with x = 0.10 is considered as a threshold concentration of the FOMT-SOMT transformation. Considering temperature dependences of resistivity, rho(T), in the presence and absence of the magnetic field, the samples (excepting for x = 0.17) exhibit a metal-insulator transition at T (P) = 60-160 K, which shifts toward lower temperatures with increasing x. In the metallic-ferromagnetic region, the rho(T) data are well fitted to a power function rho(T) = rho(0) + rho(2) T-2 + rho(4.5) T-4.5. This indicates electron-electron and electron-magnon scattering processes are dominant at temperatures T < T (P). In addition, the conduction data at temperatures T > theta(D)/2 (theta(D) is the Debye temperature) and T (P) < T < theta(D)/2 obey the small-polaron and variable-range hopping models, respectively. The values of activation energy E-p, and density of states at the Fermi level N(E-F) were accordingly determined. Here, N(E-F) increases while E-p decreases when an external magnetic field is applied. We also have found that N(E-F) increases when materials transfer from the FOMT to the SOMT, and N(E-F) value becomes smallest for the sample having the coexistence of the FOMT and SOMT (i.e., x = 0.10).
date: 2014
date_type: published
official_url: DOI: 10.1109/TMAG.2014.2301713
full_text_status: none
publication: IEEE Transactions on Magnetics
volume: 50
pagerange: 2502404
refereed: TRUE
issn: 0018-9464
citation:   Tran, Dang Thanh and Phan, T. L and Phung, Quoc Thanh and Hoang, Nam-Nhat and Duong, Anh Tuan and Yu, S. C  (2014) Electrical and Magnetotransport Properties of La0.7Ca0.3Mn1−xCoxO3.  IEEE Transactions on Magnetics, 50 .   p. 2502404.  ISSN 0018-9464