Magnetic entropy change and colossal magnetoresistance effect in the layered perovskite La1.34Sr1.66Mn2O7

摘要

Magnetocaloric and electronic properties of the layered perovskite La1.34Sr1.66Mn2O7 manganese oxide have been investigated. Broadening of the magnetic entropy change peak was observed above Curie temperature (T-c = 118 K), which can be associated with the existence of two-dimensional short-range magnetic order in the bilayered perovskite. There is an additional reinforcement of the magnetization in a narrow range under T-c when magnetic field is above similar to 2 T, leading to a positive magnetic entropy change. It is noticeable that a wide peak of magnetoresistance (MR similar to 66%) near T-c as well as two field-dependent peaks in R-T curves was found in our sample. (C) 2004 Elsevier Ltd. All rights reserved. [References: 19]