@article{oai:nagoya.repo.nii.ac.jp:00005383,
 author = {Asano, H. and Hayakawa, J. and Matsui, M.},
 issue = {25},
 journal = {Applied Physics Letters},
 month = {Jun},
 note = {Bulk samples of La_{2-2x}Ca_{1+2x}Mn_2O_7 with the layered Sr_3Ti_2O_7-type perovskite structure have been successfully synthesized and investigated with respect to their magnetic and electrical properties. It is found that La_{2-2x}Ca_{1+2x}Mn_2O_7 (x=0.25) is a metallic ferromagnet with a magnetic transition temperature T_c of 215 K. The large magnetoresistance (MR) effect with Δρ/ρ_0 of ～ 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 magnetic T_c . This behavior is quite different from that of the well-known double-exchange ferromagnets such as La_{1-x}Ca_xMnO_3, 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 La_{2-2x}Ca_{1+2x}Mn_2O_7.},
 pages = {3638--3640},
 title = {Giant magnetoresistance of a two-dimensional ferromagnet La_{2-2x}Ca_{1+2x}Mn_2O_7},
 volume = {68},
 year = {1996}
}