Robustness of magnetic and electric domains against charge carrier doping in multiferroic hexagonal ErMnO₃

Abstract

We investigate the effect of chemical doping on the electric and magnetic domain pattern in multiferroic hexagonal ErMnO 3 . Hole-and electron doping are achieved through the growth of Er 1−x Ca x MnO 3 and Er 1−x Zr x MnO 3 single crystals, which allows for a controlled introduction of divalent and tetravalent ions, respectively. Using conductance measurements, piezoresponse force microscopy and nonlinear optics we study doping-related variations in the electronic transport and image the corrsponding ferroelectric and antiferromagnetic domains. We find that moderate doping levels allow for adjusting the electronic conduction properties of ErMnO 3 without destroying its characteristic domain patterns. Our findings demonstrate the feasibility of chemical doping for nonperturbative property-engineering of intrinsic domain states in this important class of multiferroics.

Charged domain walls in improper ferroelectric hexagonal manganites and gallates

“…Aliovalent doping of h-RMnO 3 has been demonstrated to strongly modify the conductivity of charged DWs, without perturbating the DW pattern [42][43][44]. Donor doping enhances the conductivity of head-to-head DWs, while acceptor doping promotes the conductivity of tail-to-tail DWs, fully in agreement with our presented model.…”

Domains and domain walls in multiferroics

“…The electrostatic potential at the walls shifts the Fermi level into the broad valence band where the effective mass is low, leading to an enhanced conduction at the walls [105]. In order to control and optimize the electronic domain wall properties in hexagonal manganites, effects related to off-stoichiometry [118,[123][124][125][126][127][128] and aliovalent cation substitution on the A-and B-site were studied systematically [129,130]. Interestingly, recent studies suggest that the emergence of anomalous conductance is not restricted to isolated head-to-head and tail-to-tail walls in RMnO 3 : Wherever the walls intersect in the characteristic cloverleaf-like arrangement [106,116], ferroelectric vortex cores with emergent U(1) symmetry form [131][132][133].…”

Electronic bulk and domain wall properties in B -site doped hexagonal ErMnO3

“…Since the first direct observation of conducting DWs in BiFeO 3 [9], significant progress has been made on the fundamental science behind DWs. It has been established that their local properties are largely dominated by the interplay of local polarization states [25,26] and available charge carriers [27,28]. Despite this progress, the research trying to produce a functional device is still * donald.evans@ntnu.no in an early stage [29][30][31]: one of the key challenges is the optimization of emergent electronic DW behavior beyond the as-grown properties [22].…”