Hollandites as a new class of multiferroics

Abstract

Discovery of new complex oxides that exhibit both magnetic and ferroelectric properties is of great interest for the design of functional magnetoelectrics, in which research is driven by the technologically exciting prospect of controlling charges by magnetic fields and spins by applied voltages, for sensors, 4-state logic, and spintronics. Motivated by the notion of a tool-kit for complex oxide design, we developed a chemical synthesis strategy for single-phase multifunctional lattices. Here, we introduce a new class of multiferroic hollandite Ba-Mn-Ti oxides not apparent in nature. BaMn3Ti4O14.25, designated BMT-134, possesses the signature channel-like hollandite structure, contains Mn4+ and Mn3+ in a 1:1 ratio, exhibits an antiferromagnetic phase transition (TN ~ 120 K) with a weak ferromagnetic ordering at lower temperatures, ferroelectricity, a giant dielectric constant at low frequency and a stable intrinsic dielectric constant of ~200 (1-100 MHz). With evidence of correlated antiferromagnetic and ferroelectric order, the findings point to an unexplored family of structures belonging to the hollandite supergroup with multifunctional properties, and high potential for developing new magnetoelectric materials.

Green and scalable production of colloidal perovskite nanocrystals and transparent sols by a controlled self-collection process

“…S9). Moreover, the selfcollection strategy has been successfully applied to synthesize other complex metal oxides 15 .…”

Structural Defects of Silver Hollandite, AgxMn8Oy, Nanorods: Dramatic Impact on Electrochemistry

“…Structural characterization including electron microscopy revealed that it contains Mn 4þ and Mn 3þ and exhibits correlated antiferromagnetic and ferroelectric order. 20 One-dimensional ZnMn 2 O 4 nanowires exhibited high power capability at elevated current rates, attributed to enhanced kinetics of the nanowire electrode. 21 Fundamental studies involving the impact of physical and chemical properties of materials on their electrochemical properties are critical to the rational development of battery materials which may address the present and future requirements for stationary and portable power.…”

Lattice Defects Induce Multiferroic Responses in Ce, La‐Substituted BaFe0.01Ti0.99O3 Nanostructures

“…The value of maximum polarization, P max = 13.83 and 8.28 μC/cm 2 , and remanent polarization, P r = 5.45 and 2.46 μC/cm 2 with coercivity, E c = 9.53 and 6.14 kV/cm, respectively, measured for BFTO:Ce and BFTO:La. These values of polarization have an improvement than reported work on single‐phase multiferroic . This is due to nanoaggregation formation and lattice distortion enhancement in the BTO lattice.…”