Epitaxial thin films of multiferroic Bi₂FeCrO₆ with B-site cationic order

Abstract

Epitaxial thin films of Bi 2 FeCrO 6 have been synthesized by pulsed laser deposition on SrRuO 3 on (100)-and (111)-oriented SrTiO 3 substrates. Detailed X-ray diffraction and cross-section transmission electron microscopy analysis revealed a double perovskite crystal structure of the Bi 2 FeCrO 6 epitaxial films very similar to that of BiFeO 3 along with a particularly noteworthy Fe 3+ /Cr 3+ cation ordering along the [111] direction. The films contain no detectable magnetic iron oxide impurities and have the correct cationic average stoichiometry throughout their thickness. They however exhibit a slight modulation in the Fe and Cr compositions forming complementary stripe patterns, suggesting minor local excess or depletion of Fe and Cr. The epitaxial BFCO films exhibit good ferroelectric and piezoelectric properties, in addition to magnetic properties at room temperature, as well as an unexpected crystallographic orientation dependence of their room temperature magnetic properties. Our results qualitatively confirm the predictions made using the ab-initio calculations: the double-perovskite structure of Bi 2 FeCrO 6 films exhibit a Fe 3+ /Cr 3+ cation ordering and good multiferroic properties, along with the unpredicted existence of magnetic ordering at room temperature.

Geometrical lattice engineering of complex oxide heterostructures: a designer approach to emergent quantum states

“…Interestingly, the saturated magnetic moment per formula unit of the superlattice was much stronger than the signal of the film grown from the BFCO sputtering target [88] . This enhanced magnetization due to GLE sheds additional light on its potential for the development of new magnetic materials for application.…”

Infrared and magnetic characterization of multiferroicBi2FeCrO6thin films over a broad temperature range

“…The value of saturated magnetization is typical for antiferromagnets with weak ferromagnetism induced by a canted spin structure and the value of RT spontaneous magnetization corresponds well to the previously published results. 4,5,10 The low value (∼ 0.3 µ B /f.u.) of magnetization at saturation of the film regarding the expected theoretical value of 2 µ B /f.u.…”

Epitaxial thin films of the multiferroic double perovskite Bi2FeCrO6 grown on (100)-oriented SrTiO3 substrates: Growth, characterization, and optimization

“…The Bi 2 FeCrO 6 films have a double perovskite crystal structure very similar to that of BFO and exhibit a clear Fe-Cr ordering along the ͓111͔ direction. 13 In this paper, we analyze in detail the conditions for growing phase pure epitaxial films of Bi 2 FeCrO 6 by PLD on ͑100͒-oriented STO. The influence of the deposition conditions on the PLD-grown thin films in a wide range of deposition temperature T S ͑600-850°C͒ and ambient oxygen pressure PO 2 ͑10 −4 to 10 −2 mbar͒ has been investigated.…”