Phase separation, memory effects, and magnetization steps in single crystallineLa1.1Sr1.9Mn2O7

Abstract

The magnetic ground state of a single crystalline bilayered manganite ${\mathrm{La}}_{1.1}{\mathrm{Sr}}_{1.9}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ is investigated using bulk magnetic measurements. Besides large relaxation times, memory effects reminiscent of that seen in spin glasses are also observed both in the field cooled and zero field cooled measurement protocols. These indicate that this system is not a canted antiferromagnet as was reported earlier, but on the contrary has an inhomogenous magnetic ground state arising as a consequence of phase separation. We also report the observation of sharp metamagnetic steps in this bilayered manganite, similar to that seen in phase separated three-dimensional perovskites.