Influence of Sintering Temperature on Low-field Spin-polarized Tunneling Magnetoresistance of La<sub>0.7</sub>Ca<sub>0.3</sub>MnO<sub>3</sub>
Pham Thanh Phong
Do Hung Manh
Le Van Hong
Nguyen Xuan Phuc
Nguyen Van Khiem
Vu Van Hung
Abstract
In this study we report the effect of sintering temperature on the low field magnetoresistance
(LFMR) of La0.7Ca0.3MnO3 manganite synthesized through sol-gel technique. The
La0.7Ca0.3MnO3 has been sintered at 600°C, 700°C, 800°C, 900°C and 1200°C. The crystallite
as well as particle size also show strong dependence on the sintering temperature. While
the ferromagnetic – paramagnetic (FM-PM) transition temperature remains almost constant,
the metal – insulation transition temperature drop gradual and the low field magnetoresistance
(LFMR) increase with a decrease in grain size. We have analyzed our data based on the spin –
polarized transport of conduction electrons at the grain boundaries.
Tác giả
Pham Thanh Phong
Ninh Hoa Department of Education and Training, Khanh Hoa, Vietnam