Substantial magnetoelectric coupling in nanocrystalline-Fe2TeO6 at room temperature

Abstract

There is a confocal attention of the multifunctional material science and condensed matter physics research community to the room temperature (RT) magnetoelectric multiferroics through past several decades for its novel physical and chemical properties. Materials with substantial coupling at RT are still an unsaturated problem in the field of condensed matter physics. Apart from searching new magnetoelectrics, enhancement of the coupling as well as physical properties by manipulating the size dependency of these properties also very popular. Here, we report the presence of substantial magnetoelectric cooping in Nanocrystalline Fe2TeO6 (FTO) at room temperature synthesized by sol-gel process. The nano aspect of FTO is confirmed from transmission electron microscopy, where the particles of sizes 10 – 40 nm are seen. Magnetic measurement on nano-FTO confirms the antiferromagnetic nature of particles having Nѐel temperature TN = 167 K, which is much lower than that of bulk (210 K). PE loop measurement at room temperature gives the remanent polarization (Pr) value of 0.098 μC/cm2 , confirming ferroelectricity in FTO. A nonmonotonous increase in the remanent polarization is noticed when an external magnetic field is applied on the sample. This is a clear indication of prevailing substantial magnetoelectric (ME) coupling in the sample at room temperature. Quantification of magnetoelectricity is done by directly measuring the ME voltage (V) in the presence of varying dc magnetic field (H) and the ME coefficients are obtained using a quadratic relation in H. Presence of ferroelectricity and magnetoelectricity above the Nѐel temperature is very unusual phenomenon in this material. The presence of short range magnetic ordering which prevails even upto RT, much higher that of long range magnetic ordering temperature is suspected to be responsible for this.