Impurity-induced resistivity of ferroelastic domain walls in doped lead phosphate

Abstract

The topology and the trace of ferroelastic domains, namely W walls, of Cadoped lead orthophosphate (Pb 1−x , Ca x ) 3 (PO 4 ) 2 with a Ca content of 2.7% mol were studied on the monoclinic cleavage plane (100) using contact mode atomic force microscopy. Furthermore, conducting atomic force microscopy was applied using a bias voltage across the cantilever and the sample inducing a tunnelling current. As a reference a pure lead phosphate crystal was used. Only the Ca-doped lead phosphate crystals showed a considerable difference in conductivity between walls and the bulk. The conductivity in the bulk was found to be approximately 7% higher than in the domain walls. The experimental results show that ferroelastic domain walls of atomistic width can work as barriers to dielectric transport.

Landau theory of domain wall magnetoelectricity

“…It is also worth mentioning that domain walls are known to attract charge carriers and oxygen vacancies [41], [42], [43]. These could further enhance the local magnetization at the domain wall beyond the value calculated here.…”

Domain wall nanoelectronics

“…Transport measurements showed superconductivity, while magnetic measurements did not; this suggested that the superconductivity was located only at the domain walls, which provided a percolating superconductive path while occupying a small volume fraction of the crystal. Later, Bartels et al (2003) used a conducting-tip scanning probe microscope to show the converse behavior: The domain walls of a calcium-doped lead orthophosphate crystal were found to be more resistive than the domains.…”

Emerging Multiferroic Memories

“…The idea that novel properties could occur at domain walls in materials presented by Přívratská and Janovec is part of a larger field of study of the morphology and properties of domains and their walls that has taken place over the last 50 years with increasing recent attention given to the study novel functionality at domain walls [143][144][145]. For instance, recent work has demonstrated that spin rotations across ferromagnetic domain walls in insulating ferromagnets can induce a local polarization in the walls of otherwise non-polar materials [2,145], preferential doping along domain walls has been reported to induce 2D superconductivity in WO 3−x [146] and enhanced resistivity in phosphates [147], while in paraelectric (non-polar) SrTiO 3 the ferroelastic domain walls appear to be ferroelectrically polarized [148]. Taking this idea one step further, Daraktchiev et al [149,150] have proposed a thermodynamic (Landautype) model with the aim of quantitatively estimating whether the walls of BiFeO 3 can be magnetic and, if so, to what extent they might contribute to the observed enhancement of magnetization in ultrathin films.…”