SUBSTITUTED BARIUM TITANATE AND BARIUM STRONTIUM TITANATE FERROELECTRIC COMPOSITIONS

摘要

This invention provides the three novel La,Fe, La,Cr and Sm,Fe substitutedbarium titanate solid solution ferroelectric compositions with the formula Ba1-xLnxTi1-xMxO3 wherein when Ln is La, M is Fe or Cr, when Ln is Sm, M is Fe andx is from about 0.02 to about 0.06 and mixtures thereof, the novel La,Fesubstituted barium strontium titanate solid solution ferroelectriccompositions with the formula (Ba1-ySry)1-xLaxTi1-xFexO3 wherein y is greaterthan zero and less than about 0.6 and x is from about 0.01 to about 0.06 andthe novel La,Al substituted barium strontium titanate solid solutionferroelectric compositions with the formula (Ba1-ySry)1-xLaxTi1-x/4-3a/4Al.square.a(x-a)/4O3 wherein .square. denotes a vacancy, y is greater thanzero and less than about 0.6, a is from about 0.01 to about 0.06 and x is from0.02 to about 0.10 with the proviso that x is greater than or equal to a.Theselow loss tunable ferroelectric compositions are especially useful in tunablemicrowave thin film devices which fall into three types: interdigital andtrilayer capacitors, coplanar waveguides and microstrips.