Multiferroic double perovskites: Opportunities, issues, and challenges

Abstract

Despite the great technological and scientific importance, a well-controlled coupled behavior in magnetoelectric multiferroic materials at room temperature remains challenging. We demonstrate that the self-ordered A 2 B'B''O 6 (e.g., A = La, B' = Mn, and B'' = Ni) double perovskites provide a unique alternative opportunity to control and/or to induce such behavior in oxides. In this paper, we outline and discuss the various challenges and bottleneck issues related to this class of materials using La 2 NiMnO 6 as a prototype. Details of the synthesis strategies, using pulsed laser deposition as a central tool, to obtain a meticulous control over B'/B'' cation ordering is illustrated. The possible impact of Ni/Mn cation ordering on the magnetic ground states, ferromagnetic transition temperature, phonon behavior, and spin-phonon coupling are presented. Our results are also compared with the current literature on related compounds.2

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

“…[72] In this family, the B and B ′ ions are naturally ordered by forming a rock salt sublattice with B-O-B ′ super-exchange that can generate rich magnetic and topological behaviors depending on the choice of the transition metal elements. Thus, the ordered double perovskites offer an excellent engineering playground for which potential functionalities can be predicted and explored [72][73][74][75][76] . From the synthesis perspective, in the bulk the formation of an ordered double perovskite requires a relatively large difference between the chemical valences of B and B ′ ions.…”

Spin reorientation and disordered rare earth magnetism in Ho2FeCoO6

“…In figure 1 (b), the magnetic susceptibility of Ho 2 FeCoO 6 is given as χ(T ) = (χ exp − χ o ) on the left axis and the corresponding inverse susceptibility on the right axis. χ o ∼ 0.0286 emu/mol-Oe was obtained from the fit on magnetic susceptibility using Eqn (1). A linear fit to 1/(χ exp − χ o ) vs T in the range of 275 K -350 K was used to extract the effective paramagnetic moment and the Curie-Weiss temperature.…”

“…The research on double perovskites extends over bulk as well as thin films in order to realize usable multiferroic device elements [1,2,3,4]. In addition to multiferroicity [2], observation of metamagnetic steps in magnetization [5], exchange bias [6], magnetoresistance and magnetocapacitance [7] make these compounds interesting.…”

Intrinsic dielectric properties of magnetodielectric La2CoMnO6

“…In the past fifteen years, double perovskites with chemical formula RE 2 MeMnO 6 (where RE = rare earth; and Me = Ni or Co) have attracted a lot of attention because they can present very interesting physical properties, such as multiferroicity 1,2 , and a variety of electrical/magnetic couplings, with potential applications in new technologies 2,3 . In particular, La 2 CoMnO 6 (LCMO) and La 2 NiMnO 6 (LNMO) has a distinguished position among other members of the series, mainly because of their relative higher Curie temperature (T c 230K and 280K, respectively), and strong electrical-magnetic coupled phenomena like magnetoelectric (ME) 4 , magnetodielectric (MD) [5][6][7][8] , magnetoresistive (MR) 9 and colossal magnetoresistive (MCR) 10 effects.…”