Hexagonal phase stabilization and magnetic orders of multiferroicLu1−xScxFeO3

Abstract

Hexagonal LuFeO3 has drawn a lot of research attention due to its contentious room-temperature multiferroicity. Due to the unstability of hexagonal phase in the bulk form, most experimental studies focused on LuFeO3 thin films which can be stabilized by strain using proper substrates. Here we report on the hexagonal phase stabilization, magnetism, and magnetoelectric coupling of bulk LuFeO3 by partial Sc-substitution of Lu. First, our first-principles calculations show that the hexagonal structure can be stabilized by partial Sc substitution, while the multiferroic properties including the noncollinear magnetic order and geometric ferroelectricity remain robustly unaffected. Therefore, Lu1-xScxFeO3 can act as a platform to check the multiferroicity of LuFeO3 and related materials in the bulk form.Second, the magnetic characterizations on bulk Lu1-xScxFeO3 demonstrate a magnetic anomaly (probable antiferromagnetic ordering) above room temperature,~425-445 K, followed by magnetic transitions in low temperatures (~167-172 K). In addition, a magnetoelectric response is observed in the low temperature region. Our study provides useful information on the multiferroic physics of hexagonal RFeO3 and related systems.PACS numbers: 75.85.+t, 71.15.Mb,

Vortex ferroelectric domains, large-loop weak ferromagnetic domains, and their decoupling in hexagonal (Lu, Sc)FeO3

“…The X-ray spectrum obtained using a PANalytical diffractometer (Fig. 1c) is consistent with the pure h-Lu 0.6 Sc 0.4 FeO 3 phase, 14,16 and does not exhibit any measurable peak broadening or the presence of any second phases, indicating the high quality of crystals. Three 1°C/ h-cooled h-Lu 0.6 Sc 0.4 FeO 3 specimens (LSFO1-3) were prepared by mechanical cleaving to expose hexagonal a-b surfaces, and used for most of our scanning experiments.…”

“…1a) has attracted a significant research attentions, since this metastable hexagonal phase of its orthorhombic bulk form was reported to be stabilized in thin film form by epitaxial strain 12,13 or in bulk by Sc or Mn doping. [14][15][16] Samples in both forms are believed to show similar physical properties despite different approaches used for the synthesis (see Supplementary Information, note 1 for details). They exhibit robust FE well above room temperature, similar to the wellstudied multiferroic hexagonal RMnO 3 (h-RMnO 3 , R= rare earth).…”

Magnetoelectricity in multiferroics: a theoretical perspective

“…The ferroelectric Curie temperatures are considerably high (much higher than room temperature in most members) and the polarization remains moderate (typically~10 C/cm 2 ). The magnetic moments of Mn (Fe) become ordered usually at low temperatures (~100 K for Mn and a little higher for Fe) [41,42]. The Only the A2 configuration can present a net magnetization, while the magnetization is canceled between layers for the B1 case.…”

Visualizing weak ferromagnetic domains in multiferroic hexagonal ferrite thin film

“…Considering the ∼ 1 mHz noise level of our MeFM, the smallest magnetization change we can measure is δM = 1.38 × 10 −6 µ B /Å 3 . The dielectric constants of YSZ and h-LuFeO 3 film are 27 and 20, respectively 35,47 . The maximum electric field applied on the h-LuFeO 3 film is approximately 2.7 × 10 6 V/m using a simple doubledielectric layer model.…”

“…There are two effective routes to stabilize hexagonal polymorph of LuFeO 3 . One route is chemical doping of either Mn onto the Fe site or Sc onto the Lu site in bulk crystals [32][33][34][35] . The other is the epitaxial growth of thin films of the metastable phase on substrates with trigonal symmetry 36 .…”