Effect of pressure and magnetic field on bilayer La1.25Sr1.75Mn2O7 single crystal

We report the temperature dependence of susceptibility for various pressures, magnetic fields and constant magnetic field of 5 T with various pressures on La2-2xSr1+2xMn2O7 single crystal to understand the effectiveness of pressure and magnetic field in altering the magnetic properties. We find that the Curie temperature, T-c, increases under pressure (dT(c)/dP = 10.9 K/GPa) and it indicates the enhancement of ferromagnetic phase under pressure up to 2 GPa. The magnetic field dependence of T-c is about 26 K for 3 T. The combined effect of pressure and constant magnetic field (5 T) shows dT(c)/dP = 11.3 K/GPa and the peak structure is suppressed and broadened. The application of magnetic field of 5 T realizes 3D spin ordered state below T-c at atmospheric pressure. Both peak structure in chi(c) and 3D spin ordered state are suppressed, and changes to 2D-like spin ordered state by increase of pressure. These results reveal that the pressure and the magnetic field are more competitive in altering the magnetic properties of bilayer manganite La1.25Sr1.75Mn2O7 single crystal. (C) 2005 Elsevier Ltd. All rights reserved.