XRD and HREM Studies of Epitaxially Stabilized Hexagonal Orthoferrites RFeO₃ (R = Eu−Lu)

Abstract

The formation of previously unknown hexagonal modifications of orthoferrites RFeO3 (R = Eu−Lu) was observed on ZrO2(Y2O3) (111) substrates at 900 °C. XRD and HREM studies reveal epitaxial growth of the hexagonal film. The structure of the hexagonal RFeO3 was assigned to the ferroelectric space group P63 cm. The typical structural defects in the hexagonal RMnO3 films on ZrO2(Y2O3) (111) are described. Parallel deposition on perovskite substrates results in the stable perovskite phase. The epitaxial stabilization concept successfully explains the experimental results.

High-pressure structural stability of multiferroic hexagonalRMnO3(R=Y, Ho, Lu)

“…Here it is found that the oxygen position parameters do not significantly vary with pressure. Moreover, for the general hexagonal (P6 3 cm) ABO 3 (A = RE, B= Mn, Fe and Ga) system, replacement of the A and/or B site by ions of different radii does not significantly modify the atomic positions [8,29,30,31]. Mn is approximately in the centre of its oxygen environment [32].…”

Bulk magnetoelectricity in the hexagonal manganites and ferrites

“…1a) [11][12][13]17 . Recently, thin films of RFeO 3 rare-earth ferrites have been epitaxially stabilized in the hexa manganite P6 3 cm structure [20][21][22] . This new family of hexa materials exhibit ferroelectricity above room temperature, but with conflicting results as to its origin 23,24 .…”

Intrinsic magnetic properties of hexagonal LuFeO3 and the effects of nonstoichiometry

“…Using epitaxial stabilization, however, it is possible to make a metastable hexagonal polymorph of LuFeO 3 that is isostructural with YMnO 3 and other hexagonal rare-earth manganites. 21 In this hexagonal structure, LuFeO 3 has been measured to be both ferroelectric 22,23 and weakly ferromagnetic, [22][23][24] with first principles calculations predicting the ability to reverse the magnetization with a change in polarization. 25 It was recently reported that h-LuFeO 3 is antiferromagnetically ordered at room temperature with a canted antiferromagnetic ordering at T N = 130 K, 23 making it one of the few known room-temperature multiferroics (in this work we will refer to the onset of canted antiferromagnetic order, which is what we can measure, as the Néel temperature).…”