Pseudomorphic strain induced strong anisotropic magnetoresistance over a wide temperature range in epitaxial La0.67Ca0.33MnO3 /NdGaO3„001…films

摘要

Strong anisotropic magnetoresistance u0002AMRu0003 was observed in La0.67Ca0.33MnO3 films grownncoherently on the orthorhombic NdGaO3u0002001u0003 substrates. With an increased orthorhombic latticendistortion due to the pseudomorphic strain, the films show not only a ferromagnetic-metal u0002FMu0003ntransition at TC of u0004265 K, but also the phase coexistence of FM and antiferromagnetic-insulatornbelow u0004250 K. The phase competitions are very sensitive to the magnetic field, and morenstrikingly, to its orientations with respect to the crystal axes resulting in a large AMR in a broadntemperature range, in addition to the conventional one peaked near TC. The films also show uniaxialnmagnetic anisotropy with the easy axis along the elongated b axis, suggesting that it is the strainninduced spin-orbit-lattice coupling and the resultant phase competitions that control the AMR innepitaxial manganite films. © 2010 American Institute of Physics. u0005doi:10.1063/1.3524193u0006nu0004doi:10.1063/1.3526378