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Large low-field magnetoresistance over a wide temperature range induced by weak-link grain boundaries in La0.7Ca0.3MnO3

Journal Article


Abstract


  • Polycrystalline bulk porous samples with a large number of weak-link grain boundaries and high density polycrystalline bulk samples with strong-link boundaries were synthesized by conventional solid-state reaction and a partial melting technique. The weak-link samples showed large magnetoresistance (MR,Δρ/ρH=[ρ0-ρ H]/ρ0), 20-30%, at a low magnetic field of 300 mT and over a wide temperature range from the magnetic transition at 235 to 77 K. The partially melted samples exhibited the same magnetoresistance behavior as that of single crystals with a maximum peak MR of 15% at a narrow temperature range around the ferromagnetic transition. It is suggested that grain boundaries are necessary but not sufficient to account for the MR at low field over a large temperature range. Weak-link grain boundaries rather than strong-link boundaries are responsible for the MR at low field over a large temperature range. © 1998 American Institute of Physics.

Publication Date


  • 1998

Citation


  • Wang, X. L., Dou, S. X., Liu, H. K., Ionescu, M., & Zeimetz, B. (1998). Large low-field magnetoresistance over a wide temperature range induced by weak-link grain boundaries in La0.7Ca0.3MnO3. Applied Physics Letters, 73(3), 396-398. doi:10.1063/1.121846

Scopus Eid


  • 2-s2.0-0009418582

Start Page


  • 396

End Page


  • 398

Volume


  • 73

Issue


  • 3

Abstract


  • Polycrystalline bulk porous samples with a large number of weak-link grain boundaries and high density polycrystalline bulk samples with strong-link boundaries were synthesized by conventional solid-state reaction and a partial melting technique. The weak-link samples showed large magnetoresistance (MR,Δρ/ρH=[ρ0-ρ H]/ρ0), 20-30%, at a low magnetic field of 300 mT and over a wide temperature range from the magnetic transition at 235 to 77 K. The partially melted samples exhibited the same magnetoresistance behavior as that of single crystals with a maximum peak MR of 15% at a narrow temperature range around the ferromagnetic transition. It is suggested that grain boundaries are necessary but not sufficient to account for the MR at low field over a large temperature range. Weak-link grain boundaries rather than strong-link boundaries are responsible for the MR at low field over a large temperature range. © 1998 American Institute of Physics.

Publication Date


  • 1998

Citation


  • Wang, X. L., Dou, S. X., Liu, H. K., Ionescu, M., & Zeimetz, B. (1998). Large low-field magnetoresistance over a wide temperature range induced by weak-link grain boundaries in La0.7Ca0.3MnO3. Applied Physics Letters, 73(3), 396-398. doi:10.1063/1.121846

Scopus Eid


  • 2-s2.0-0009418582

Start Page


  • 396

End Page


  • 398

Volume


  • 73

Issue


  • 3