No abstract

Uniaxial magnetic anisotropy has been observed in La0.7Sr0.3MnO3 thin films grown on top of multiferroic BiFeO3 with ferroelectric stripe domains (see Figure). The magnetic easy axis of La0.7Sr0.3MnO3 correlates with the ferroelectric stripe domains. A possible spin coupling model at the La0.7Sr0.3MnO3/BiFeO3 interface is established between ferromagnetic and antiferromagnetic orders to explain this phenomenon.

BiFeO 3 (BFO) films were processed on BaTiO3 (BTO) buffered (111) Pt/Ti/SiO2/Si substrate by pulsed laser deposition. Improved ferroelectric properties, as well as induced ferromagnetism, were observed by the insertion of a BTO layer for rather thick BFO films (450 nm) deposited at an oxygen pressure of 40 mTorr. Reduced leakage current, coercive field, and increased ferroelectric saturation of BFO/BTO bilayer films were obtained and compared with those of BFO films. In order to better understand the buffer layer effect on the magnetic properties, two thinner (140 and 220 nm) BFO films were also deposited and investigated. Both films showed ferromagnetic hysteresis loops and larger in-plane magnetization than out-of-plane magnetization. By introducing the BTO barrier layer, the remnant and saturated magnetizations were also increased. These results demonstrated not only the interface constraint effect but also a coupling between ferroelectric BTO and magnetic BFO, which deserve further investigation.