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Indian Journal of Pure & Applied Physics (IJPAP) >
IJPAP Vol.42 [2004] >
IJPAP Vol.42(01) [January 2004] >
| Title: | Study of low field magneto-resistance in La0.67A0.33MnO3 [A ≡ Ca, Ba, Sr] screen printed films |
| Authors: | Khare, Neeraj
Moharil, U P
Singh, B
Gupta, A K |
| Keywords: | Magneto-resistance
Polycrystalline films
Epitaxial films
Laser ablation technique
spin Polarized tunneling |
| Issue Date: | Jan-2004 |
| Publisher: | CSIR |
| Abstract: | Screen printed polycrystalline films of La0.67A0.33MnO3
[A ≡ Ca, Ba, Sr] have been found to exhibit substantially large magneto-resistance
at low fields and low temperature as compared to an epitaxial La0.67Ba0.33MnO3
film prepared by laser ablation technique. A value of magneto-resistance ratio
(MRR) of 6 % has been achieved even at a dc field of 600 Oe at 77 K.
Temperature dependence of MRR of the screen-printed films show that MRR
increases with decrease of the temperature. This MRR-T behaviour shows that
magneto-resistance in screen printed films has its origin in grain boundaries.
The variation of MRR of these films with magnetic field at 77 K shows sharp
increase in the field 0-1 kOe and slower increase for the field 1-3 kOe. Sharp
increase in the MRR has been attributed to spin polarized tunnelling occurring
across the grain boundaries, where as the slower increase in MRR for a field
variation of 1-3 kOe is due to suppression of spin disorders present in the
grain boundary region in the polycrystalline films. |
| Page(s): | 62-66 |
| ISSN: | 0975-1041 (Online); 0019-5596 (Print) |
| Source: | IJPAP Vol.42(01) [January 2004]
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