H.B. Sharma

OPTICAL AND STRUCTURAL PROPERTIES OF NANO-SIZED BARIUM STRONTIUM TITANATE (Ba0.6Sr0.4TiO3) THIN FILM

Barium strontium titanate (Ba0.6Sr0.4TiO3) or BST thin films on quartz substrates have been prepared by using a modified sol-gel processing technique. The starting materials are barium 2-ethylhexanoate Ba[CH3(CH2)3CH(C2H5)CO2]2, strontium 2-ethylhexanoate Sr[CH3(CH2)3CH(C2H5)CO2]2 and titanium (IV) isopropoxide Ti[CH3CH3CHO]4. The precursors Ti[CH3CH3CHO]4 except were synthesized in the laboratory. Transparent and crack-free films were fabricated on quartz substrates by spin coating. The as-fired films were found to be amorphous, which crystallized to cubic phase after annealing at 550°C in air for 1 hr. In this paper, we report the structural and optical properties of BST thin films prepared by the modified sol-gel process.

Structural and Optical Properties of Barium Strontium Titanate (Ba0.5Sr0.5TiO3) Thin Films

Ferroelectric Barium Strontium Titanate (Ba0.5Sr0.5TiO3) or BST thin films on quartz substrates have been prepared by using a modified sol gel processing technique. The starting materials are Barium 2-ethylhexanoate Ba[CH3(CH2)3CH(C2H5)CO2]2, Strontium 2-ethylhexanoate Sr[CH3(CH2)3CH(C2H5)CO2]2 and Titanium(IV) isopropoxide [TiOCH(CH3)2]4. The precursors except [TiOCH(CH3)2]4 were synthesized in the laboratory. Transparent and crack-free films were fabricated on quartz substrates by spin coating. The as-fired films were found to be amorphous, which crystallized to cubic phase after annealing at 550°C in air for 1 hr. In this paper we report the structural and optical properties of BST films prepared by the modified sol-gel process. Communicated by Prof. E. C. Subbarao

Dielectric Study on the Alignment or Orientation of N(4-n-heptyloxy benzylidene)4´-n-butylaniline and the Anomalous Dielectric Behavior in the Smectic G Phase

ABSTRACT The present article reports on the alignment or orientation of a particular compound N(4-n-heptyloxy benzylidene)4´-n-butylaniline through dielectric study. The effect of using two different alignment layers (for homogenous alignment) and doping silver nanoparticles (0.25% by weight) on the behavior in dielectric property with varying temperature and biasing electric field was studied in terms of liquid crystal alignment or orientation using the mechanism proposed by earlier workers. The study includes the anomalous dielectric behavior in SmG phase by presenting a technique for the analysis of the absorption process, which exists only in SmG phase at fixed frequency while varying temperature, is also presented.