Anomaly in structural noncentrosymmetry around T sub(N) n bulk and nanoscale BiFeO sub(3)

Using high resolution powder neutron diffraction data, we show that there is a distinct anomaly in the structural noncentrosymmetry around the magnetic transition point T sub(N) for bulk and nanoscale BiFeO sub(3). It appears that the structural noncentrosymmetry - which gives rise to the ferroelectric polarization - is suppressed anomalously by ~1% (of the average noncentrosymmetry at above the magnetic transition) in the bulk sample and by ~12% in the nanoscale sample as the magnetic transition is approached from higher temperature. This observation shows that the multiferroic coupling improves in the nanoscale sample which is expected to brighten the application prospects of nanoscale BiFeO sub(3) in nanospintronics-based sensor devices. PACS Nos. 75.70.Cn, 75.75.-c