Effects of Zr substitution on structures and ferroelectric properties of Bi_3.25La_0.75Ti₃O₁₂thin films

Abstract

Thin films of Bi3.25La0.75Ti3O12 (BLT) and B-site substituted BLT by Zr, i.e. Bi3.25La0.75Ti3−xZrxO12 (BLTZx, x = 0.20, 0.50, 0.75, 1.00 and 1.50) were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Structures and electrical characteristics of the polycrystalline films were studied as functions of Zr composition. Structures were investigated by x-ray diffraction, scanning electron microscopy and Raman spectroscopy. It is revealed that the Zr substitution does not destroy the layered structures of BLT but the Zr substitution tolerance is limited. With increasing Zr composition, generally, the octahedra-related vibration modes show a significant low-frequency shift. Compared with the well-known BLT films, the BLTZ0.20 films have larger remnant polarization (Pr), smaller coercive field (Ec) and better fatigue resistance. However, further increasing Zr composition leads to weakened ferroelectricity of the BLTZx films with decreased Pr and reduced fatigue resistance. The effects of Zr substitution on structures and ferroelectric properties of BLT and the correlation between structures and properties are discussed in detail.

The influence of the thickness of TiO2seeding layer on structural and electrical properties of Bi3.15Nd0.85Ti3O12thin films

“…Recently, bismuth layered structure ferroelectrics (BLSFs) thin films were widely investigated due to their superior properties [1,2]. Among them, Bi 4 Ti 3 O 12 (BTO) is known to be a typical kind of layer-structured ferroelectrics.…”

Ferroelectric properties of Bi4Zr0.5Ti2.5O12 thin films prepared on LaNiO3 bottom electrode by sol-gel method

“…Many papers that reported the substituted BTO in the B-site focused on the high valent cations such as V 5+ and W 6+ substituting for Ti 4+ [5,6] , but few papers reported the substitution of the equal valent cations such as Zr 4+ substituting for Ti 4+ . Zhang et al [7,8] showed that the Zr-doped bismuth titanate (Bi 4 Zr 0.5 Ti 2.5 O 12 , BZT) thin films had excellent ferroelectric properties. The properties of B-site Zr substituted BTO films are worth studying.…”

FERROELECTRIC PROPERTIES OF Zr-DOPED Bi3.25La0.75Ti3O12 THIN FILM DEPOSITED BY RF MAGNETRON SPUTTERING

“…Undoped BTO shows a very larger spontaneous polarization along the a-axis (about 50 µC/cm 2 ), but BTO thin films have much lower of switching polarization and suffer from poor fatigue endurance [6]. Some researchers have suggested that proper ion substitution (at the A-site with Sm 3+ , Ca 2+ , Sr 2+ , La 3+ , Nd 3+ ion or B-site with V 5+ , Ta 5+ , Nb 5+ , W 5+ , Zr 4+ ion and both A-and B-sites) in the perovskite-type unit of BTO can effectively optimize the ferroelectric properties [7,8]. Takayuki et al reported that excellent ferroelectric propertied are obtained by co-substitution of La 3+ and V 5+ in BTO thin films using a metalorganic chemical vapor deposition [9].…”