Room-temperature ferromagnetism and ferroelectricity of nanocrystalline La2Ti2O7

La2Ti2O7 nanocrystalline powders and pellets were prepared by sol–gel method. The nanocrystalline powders present room-temperature ferromagnetism (FM). The vacuum annealing enhances FM, showing that the observed room-temperature FM for La2Ti2O7 possibly originates from oxygen vacancies at/near surfaces of nanograins. La2Ti2O7 pellets annealed at 1000 °C for 1 h show the coexistence of ferromagnetism and ferroelectricity (FE) at room temperature. Meanwhile, the room-temperature magnetodielectric (MD) effect was also observed in the La2Ti2O7 multiferroic pellet, indicating the coupling between magnetic and electric properties. The value of Δɛr/ɛr(0) for La2Ti2O7 multiferroic pellet reaches 39.3% at 1 kHz under H = 6 kOe.