Epr and magnetic properties on lacamno manganites Report as inadecuate




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Electron paramagnetic resonance EPR and AC Susceptibility measurements were carried out as a function of temperature on La0,7Ca0,3MnO3 polycrystalline samples. The samples displayed a transition from paramagnetic-insulator to ferromagnetic-metal at Tc around 261K. Tc was determined from the inverse of the real part of a.c. susceptibility 1-X’ vs temperature, which follows a simple Curie-Weiss behavior. The inverse of the EPR intensity also follows a Curie-Weiss type behavior down toTEPR = 253 K

The structure of the samples as determined by X-Ray diffraction XRD corresponds to a single perovskite phase with orthorhombic unit cell., Electron paramagnetic resonance EPR and AC Susceptibility measurements were carried out as a function of temperature on La0,7Ca0,3MnO3 polycrystalline samples. The samples displayed a transition from paramagnetic-insulator to ferromagnetic-metal at Tc around 261K. Tc was determined from the inverse of the real part of a.c. susceptibility 1-X’ vs temperature, which follows a simple Curie-Weiss behavior. The inverse of the EPR intensity also follows a Curie-Weiss type behavior down toTEPR = 253 K

The structure of the samples as determined by X-Ray diffraction XRD corresponds to a single perovskite phase with orthorhombic unit cell.

Tipo de documento: Artículo - Article

Palabras clave: LaCaMnO manganites, EPR, a.c. susceptibility., LaCaMnO manganites, EPR, a.c. susceptibility.





Source: http://www.bdigital.unal.edu.co


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18 Revista de Fı́sica, No 36, Junio 2008 momento EPR and Magnetic Properties on LaCaMnO manganites J.
A.
Olarte1 , A.
Mariño2 1 Facultad Tecnológica, Universidad Distrital Francisco José de Caldas, Bogotá D.C. 2 Departamento de Fı́sica, Universidad Nacional de Colombia, Bogotá D.C., Colombia. Abstract Electron paramagnetic resonance (EPR) and AC Susceptibility measurements were carried out as a function of temperature on La0,7 Ca0,3 M nO3 polycrystalline samples.
The samples displayed a transition from paramagnetic-insulator to ferromagnetic-metal at Tc around 261K.
Tc was determined from the inverse of the real part of a.c.
susceptibility (1-χ0 ) vs temperature, which follows a simple Curie-Weiss behavior.
The inverse of the EPR intensity also follows a Curie-Weiss type behavior down to TEP R = 253K.
The structure of the samples as determined by X-Ray diffraction (XRD) corresponds to a single perovskite phase with orthorhombic unit cell. Keywords: LaCaMnO manganites, EPR, a.c.
susceptibility 1. Introduction The phenomenon called anisotropic magneto-resistance (AMR) is the change of resistance of a conductor when it is placed in an external magnetic field.
The maximum AMR effect is defined as ∆R-R = R(j--M ) − R(j ⊥ M )-R(j ⊥ M ) (1) The main mechanism behind AMR is spin-orbit scattering of the spin polarized charge carriers, which results in an anisotropic angular dependence of the current density j relative to the magnetization M .
However, compared with exchange interaction, spin-orbit coupling is relative weak, which produces small AMR effect of a few percent in some Ni-based alloys. J.
A.
Olarte: E-mail: jaolarte@unal.edu.co EPR and Magnetic Properties on LaCaMnO manganites 19 This phenomenon was observed at the first time (1858) by W. Thompson (later Lord Kelvin) in iron and nickel in the presence of a magnetic field.
The phenomenon magnetoresistance caused the electrical conductivity of a ferromagnetic material depend of th...






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