Giant magnetoresistance of a two‐dimensional ferromagnet La2−2xCa1+2xMn2O7
作者:
H. Asano,
J. Hayakawa,
M. Matsui,
期刊:
Applied Physics Letters
(AIP Available online 1996)
卷期:
Volume 68,
issue 25
页码: 3638-3640
ISSN:0003-6951
年代: 1996
DOI:10.1063/1.115755
出版商: AIP
数据来源: AIP
摘要:
Bulk samples of La2−2xCa1+2xMn2O7with the layered Sr3Ti2O7‐type perovskite structure have been successfully synthesized and investigated with respect to their magnetic and electrical properties. It is found that La2−2xCa1+2xMn2O7(x=0.25) is a metallic ferromagnet with a magnetic transition temperatureTcof 215 K. The large magnetoresistance (MR) effect with &Dgr;&rgr;/&rgr;0of ∼60% at 1.8 T was observed in a wide temperature range below a cusp temperature in resistivity of 96 K, which is well below the magneticTc. This behavior is quite different from that of the well‐known double‐exchange ferromagnets such as La1−xCaxMnO3, where large MR effects are restricted to a narrow temperature range around the ferromagnetic transition. The present result could be interpreted by using the double‐exchange theory incorporating the anisotropy resulting from the two‐dimensional Mn‐O‐Mn networks in La2−2xCa1+2xMn2O7. ©1996 American Institute of Physics.
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