Magnetic and Electrotransport Properties of the Anion-Deficient Manganites with Perovskite Structure |
| |
Authors: | S. V. Trukhanov I. O. Troyanchuk A. V. Trukhanov H. Szymczak R. Szymczak M. Baran |
| |
Affiliation: | (1) Institute of Solids and Semiconductor Physics, NAS, P.Brovka str. 17, 220072 Minsk, Belarus;(2) Vitebsk State University, Moscow av. 33, 210036 Vitebsk, Belarus;(3) Institute of Physics , PAS, Lotnikov str, 32/46 02-668 Warsaw, Poland |
| |
Abstract: | The chemical phase content and microstructure as well as magnetic and magnetotransport properties for the doped anion-deficient La3+1-xSr2+xMn3+O2–3-x/2 orthomanganites have been experimentally studied. The high-quality anion-deficient ceramic with controlled chemical phase content and microstructure has been obtained from the parent stoichiometric one at the 800 C in vacuum. The average grain size is ~5 m. It is established that the samples in the region of 0 x 0.125 are O-orthorhombic perovskites whereas in the 0.175 x 0.30—rhombohedric. As doping level increases along with the oxygen vacancies number the samples in ground state undergo a transition from the antiferromagnet A-type (x=0) through the inhomogeneous magnetic state (0 < x 0.175 to the cluster spin glass one (0.175 < x 0.30. The temperature of magnetic moment freezing is ~ 45 K. All the samples are semiconductors and show considerable magnetoresistance over a wide temperature range with peak for x = 0.175 only. Fitting of the electrical resistivity to T–1 and T–1/4 realized. The concentration dependences of the activation energy, spontaneous magnetization, coercivity as well as magnetic transition temperatures for the anion-deficient La3+1-xSr2+xMn3+O2–3-x/2 ortomanganites have been established. Obtained experimental results are interpreted in terms of the oxygen vacancies, isotropic superexchange Mn3+-O–Mn3+ interactions and phase separation models. |
| |
Keywords: | manganites magnetoresistance oxygen vacancies phase separation. |
本文献已被 SpringerLink 等数据库收录! |
|