Pr doped bismuth ferrite ceramics with enhanced multiferroic properties.

Pr modified Bi(0.9-x)La(0.1)Pr(x)FeO(3) (BLPFO-x, x = 0, 0.1 and 0.2) ceramics were prepared by the conventional method based on the solid state reaction of mixed oxides and a detailed study of electrical and magnetic properties of Pr modified bismuth ferrite (BLPFO) is reported. X-ray analysis shows the formation of a bismuth ferrite rhombohedral phase. Pr doping significantly increases the resistivity and leads to a successful observation of electrical polarization hysteresis loops. All the samples have been found to possess a spontaneous magnetic moment at room temperature which increases further at low temperatures. The strong dependence of remnant polarization and dielectric constant on the strength of magnetic field is a direct evidence of magnetoelectric coupling in BLPFO-2 ceramics.

Observation of the room temperature magnetoelectric effect in Dy doped BiFeO(3).

Polycrystalline Bi(1-x)Dy(x)FeO(3) (x = 0.0, 0.03, 0.05, 0.07 and 0.1) ceramics have been prepared via a mixed oxide route. The effect of Dy substitution on the dielectric, ferroelectric, and magnetic properties of the BiFeO(3) multiferroic perovskite is studied. Experimental results suggest that in the Bi(1-x)Dy(x)FeO(3) system, increase of the Dy concentration leads to effective suppression of the spiral spin structure of BiFeO(3), resulting in the appearance of net magnetization. An anomaly in the dielectric constant (ε) was observed in the vicinity of the antiferromagnetic transition temperature. All compositions show saturated polarization-field (P-E) curves. As a result, improved multiferroic properties of Bi(0.9)Dy(0.1)FeO(3) ceramics with remnant polarization and magnetization (2P(r) and 2M(r)) of 7.98 µC cm(-2) and 0.024 emu g(-1), respectively, were established. An enhancement in remnant polarization after poling the samples in the magnetic field was evidence of magnetoelectric coupling at room temperature.

A survey of bryophytes for presence of cholinesterase activity.

The neurotransmitter acetylcholine (ACh) is present in plants including bryophytes. The first biochemical evidence for ACh hydrolysis by enzyme cholinesterase (ChE) in bryophytes is presented. Thirty-nine species belonging to 16 families of bryophytes were surveyed for ChE activity. Thirty species belonging to 13 families showed ChE activity. Of the bryophytes tested, Anoectangium bicolor showed the highest ChE activity. Widespread distribution of ChE in bryophytes indicates their suitability as a system to study the role of ACh in plants.