A Polar Corundum Oxide Displaying Weak Ferromagnetism at Room Temperature

Abstract

Combining long-range magnetic order with polarity in the same structure is a prerequisite for the design of (magnetoelectric) multiferroic materials. There are now several demonstrated strategies to achieve this goal, but retaining magnetic order above room temperature remains a difficult target. Iron oxides in the +3 oxidation state have high magnetic ordering temperatures due to the size of the coupled moments. Here we prepare and characterize ScFeO3 (SFO), which under pressure and in strain-stabilized thin films adopts a polar variant of the corundum structure, one of the archetypal binary oxide structures. Polar corundum ScFeO3 has a weak ferromagnetic ground state below 356 K—this is in contrast to the purely antiferromagnetic ground state adopted by the well-studied ferroelectric BiFeO3.

Direct visualization of magnetic‐field‐induced magnetoelectric switching in multiferroic aurivillius phase thin films

“…1 The unique advantage of single-phase magnetoelectric multiferroics is that not only could they find application in high storage density, low-power memory devices that can be electrically written and magnetically read, but also memory technologies with four-state logic might be achieved by constructing devices that exploit the presence of both ferroelectric and ferromagnetic states 2 -representing a clear improvement over current two-state logic devices. However, there are relatively few [3][4][5][6][7][8] materials demonstrating ferroelectric and ferromagnetic properties in a single-phase at room temperature. Due to conflicting electronic structure requirements for ferroelectricity (empty d orbitals) and ferromagnetism (partially filled d orbitals), the two properties tend to be mutually exclusive.…”

Magnetic Structure and Ordering of Multiferroic HexagonalLuFeO3

“…If both order parameters are coupled, these materials would enable new devices ranging from magnetic field sensors to magnetic random access memory. Unfortunately, single-phase multiferroics are extraordinarily rare; thus far only four room temperature single-phase multiferroics have been reported: BiFeO 3 [3], BiCoO 3 [4], corundum ScFeO 3 [5], and most recently hexagonal LuFeO 3 (h-LuFeO 3 ) [6]. The latter compound, h-LuFeO 3 was found to be isostructural with YMnO 3 ( Fig.…”

Intrinsic magnetic properties of hexagonal LuFeO3 and the effects of nonstoichiometry

“…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). 10,11,23,26,27 In this letter, we determine the intrinsic magnetic properties of h-LuFeO 3 by first growing a set of samples in a compositional-spread geometry that have a range of ∼ ±10% variations in cation stoichiometry. While these films appear from x-ray diffraction (XRD) to be single phase, the nonstoichiometry becomes apparent in scanning transmission electron microscopy (STEM) and atomic force microscopy (AFM) measurements.…”