| |
 |
UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 14:28 |
 |
|
|
|
Conference: Bucharest University Faculty of Physics 2008 Meeting
Section: Solid State Physics and Materials Science
Title:
Transport phenomena and magnetic structure of La0.54Ho0.11Sr0.35Mn1-xCuxO3 manganites
Authors:
Mihail Liviu Craus[1/2], Nicoleta Cornei[3], Maria Balasoiu[2/4], Mihai Lozovan[1], Raul Erhan[2/4]
Affiliation:
1 National Institute of Research and Development for Technical Physics, Blvd. D. Mangeron 47, Iasi,700050 Romania;
2 Joint Institute for Nuclear Research-Laboratory of Neutron Physics, Dubna, Joliot-Curie 6, 141980 Dubna, Region Moskva, Russia;
3 Chemistry Faculty of “Al.I.Cuza” University, Carol I, 11, Iasi,700506 Romania
4 Horia Hulubei National Institute of Physics and Nuclear Engineering, Atomistilor 407, P.O.BOX MG-6, Bucharest - Magurele, ROMANIA
E-mail
craus@phys-iasi.ro
Keywords:
magnetic/crystalline structure, magnetoresistance, SANS
Abstract:
The La0.54Ho0.11Sr0.35Mn1-xCuxO3 manganites were obtained by sol-gel method, using oxides and acetates. Finally the samples were treated in air at 1200 oC for 15 h. The samples were investigated by X-ray diffraction using a HUBER diffractometer with GUINIER CAMERA 670 and CuKalfa1 radiation. Lattice constants, space group, positions of cations/anions in the unit cell, average size of the crystalline blocks were obtained with CeckCell and Rietveld programs. The samples contain only a perovskite phase, with orthorhombic structure (S. G. – Pnma). The variation of the specific/molecular magnetization with temperature was determined by using a Foner-type magnetometer with a data acquisition system, between 77 and 550 K. The transport phenomena were investigated at H=0 and H=1,8 T fields using a four-probe method and a data acquisition system. SANS measurements were performed at GeNF-Germany at room temperature. The substitution of the Mn cation with Cu leads to an increases of the Curie temperature (312 K < TC < 340 K). A typical magnetoresistive behavior was observed for all samples. The transition temperature from the metallic to the semiconductor (insulator) state increases with the decrease of Mn / Cu ratio in the samples. SANS results were discussed in correlation with observed magnetoresistance and magnetic properties of manganites.
|
|
|
|