In:
Journal of Applied Physics, AIP Publishing, Vol. 87, No. 9 ( 2000-05-01), p. 5582-5584
Abstract:
Magnetization, resistance, and current–voltage (I–V) measurements have been performed in La0.5Sr0.5MnO3 compact prepared by pressing sol-gel nanoparticles (46 nm) at 723 K with a high pressure (4 GPa). The pressed compound orders ferromagnetically at 340 K (TC) and has a substantial drop in the thermomagnetic curve below 158 K (TDP). After undergoing a metal–to–semiconductor transition at 140 K (TMS), the compound reenters into a strong semiconducting state below 60 K, demonstrating a charge localized behavior induced by the small grain rather than the magnetic disorder which is related with the frozen spin clusters below TDP. Instead of showing a feature near TMS, the magnetoresistance (MR) ratio increases almost linearly with decreasing temperature. The large low field MR corresponding to the sharp rise of magnetization is obtained at 5 K and, evidenced as the spin polarized intergrain tunneling (SPIT) effect by the nolinear I–V curve. Although La0.5Sr0.5MnO3 has a relatively high TC, the SPIT MR decays rapidly from 17.6% (5 K, 0.3 T) to 7.6% (150 K, 0.3 T), indicating that if trying to put the low field sensitivity of SPIT MR into application at room temperature, the selected compound having a higher TC seems to be a prerequisite.
Type of Medium:
Online Resource
ISSN:
0021-8979
,
1089-7550
Language:
English
Publisher:
AIP Publishing
Publication Date:
2000
detail.hit.zdb_id:
220641-9
detail.hit.zdb_id:
3112-4
detail.hit.zdb_id:
1476463-5
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