Magneto-transport and magnetic properties of (1–x)La0.7Ca0.3MnO3+xAl2O3 composites

Low-field magnetoresistance of (1- x )La 0.7 Ca 0.3 MnO 3 + x La 1.5 Sr 0.5 NiO 4 nanocomposite

“…The ferromagnetic (FM) to paramagnetic (PM) phase transition temperature (T C ) determined as the peak of dM(T )/dT (see figure 3(b)) is about 252 K and almost independent of LSNO content in the samples. A similar result has also been reported earlier on LCMO nanoparticles [4,14,15]. The magnetic transition temperature was practically the same for all the samples.…”

“…The values of the transition temperature are 251, 197, 145, 130 and 65 K for the samples with x = 0.0, 0.05, 0.10, 0.15 and 0.20, respectively. A similar increase of ρ values as well as the decrease of T MI in the composites have been reported for LCMO : Al 2 O 3 [4], and LCMO : CuO [2]. The metal-insulator transition is completely suppressed in our experimental measurement range for doping levels higher than 20% (x > 0.2).…”

“…Nowadays, researchers are focusing on obtaining a large value of the magnetoresistance (MR) at a low field. Many attempts have been made to enhance the LFMR effect in perovskite manganites by mixing CMR materials with a secondary phase, which could be an insulator [2][3][4][5], a magnetic material [6,7], or a metal [8,9]. Although these behaviours of the manganite composites have been extensively studied, their physical origins remain unknown.…”

Magneto-transport characteristics of electron-doped Ca0.85Sm0.15MnO3 manganite: Hopping and tunneling

“…With an increase of temperature the difference between envelope and virgin curves is gradually weakened due to decrease in arrested FM fraction. Noticeably, the hysteresis is completely disappeared at 200 K. In order to have an insight about the mechanism of observed MR we have tried to fit our experimental virgin curve (MR versus H data) with a phenomenological model namely spin polarized tunneling model [28,29]. In this model, different contributions in MR such as: field independent part coming from nonmagnetic defects and phonon scattering (R 0 ), field dependent part at low field due to the spin polarized tunneling (R SPT ) between adjacent grains and the intrinsic MR (R INT ) at high field due to the double exchange mechanism have been considered.…”

Implementación de una interfaz gráfica para el estudio de propiedades de magneto transporte en bicapas de manganitas tipo perovskita

“…Se obtuvieron resultados de resistividad y magnetorresistencia en función de la temperatura y del campo magnético externo aplicado. Las curvas de resistividad en función de la temperatura presentaron un mínimo alrededor de tierras raras divalentes de metales alcalinos respectivamente) han sido ampliamente estudiadas [1], [2]. La propiedad más fundamental de estos materiales es la fuerte correlación entre la estructura y las propiedades magnéticas y de transporte.…”