Single or Vortex Ferroelectric and Ferromagnetic Domain Nanodot Array of Magnetoelectric BiFeCoO.

Nanodots composed of multiferroic cobalt-substituted BiFeO, a ferroelectric ferromagnet at room temperature, are fabricated by pulsed laser deposition using anodized porous alumina as masks. The obtained nanodots are approximately 60 nm in diameter, more than 10 nm in thickness, and approximately 70 Gbit/in. in density.

Out-of-plane polarization reversal and changes in in-plane ferroelectric and ferromagnetic domains of multiferroic BiFeCoO thin films by water printing.

BiFeCoO is a promising material for an ultra-low-power-consumption nonvolatile magnetic memory device because local magnetization reversal is possible through application of an electric field. Here, changes in ferroelectric and ferromagnetic domain structures in a multiferroic BiFeCoO thin film induced by "water printing", which is a polarization reversal method involving chemical bonding and charge accumulation at the interface between the liquid and the film, was investigated. Water printing using pure water with pH = 6.

Magnetization controlled by crystallization in soft magnetic Fe-Si-B-P-Cu alloys.

Soft magnetic materials have low coercive fields and high permeability. Recently, nanocrystalline alloys obtained using annealing amorphous alloys have attracted much interest since nanocrystalline alloys with small grain sizes of tens of nanometers exhibit low coercive fields comparable to that of amorphous alloys. Since nanocrystalline soft magnetic materials attain remarkable soft magnetic properties by controlling the grain size, the crystal grains' microstructure has a substantial influence on the soft magnetic properties.

SrVFeO: A Vacancy-Ordered Fe-Based Perovskite Exhibiting Room-Temperature Magnetoresistance.

We report room-temperature (RT) magnetoresistance (MR) in a novel Fe-based perovskite, SrVFeO. This compound contains ordered oxygen vacancies in every fifth primitive perovskite (111) plane, leading to a layered structure consisting of triple-octahedral and double-tetrahedral layers. Along with the oxygen vacancies, the transition-metal ions are also ordered: the octahedral sites are occupied by 100% of Fe ions, while the tetrahedral sites are occupied by 25% of Fe ions and 75% of V ions.

Stabilized Charge, Spin, and Orbital Ordering by the 6s Lone Pair in BiPbMnO.

Bi and Pb ions with charge degree of freedom depending on 6 and 6 electronic configurations were combined with the Mn ion in a perovskite oxide. Comprehensive theoretical and experimental investigations revealed the BiPbMnMnO charge ordered state with CE-type spin and d orbital orderings as observed in LaCaMnO, NdSrMnO, and BiSrMnO. The charge and orbital orderings were preserved above 500 K owing to the stereochemical activity of Bi and Pb ions which stabilized the structural distortion.

High mobility approaching the intrinsic limit in Ta-doped SnO films epitaxially grown on TiO (001) substrates.

Achieving high mobility in SnO, which is a typical wide gap oxide semiconductor, has been pursued extensively for device applications such as field effect transistors, gas sensors, and transparent electrodes. In this study, we investigated the transport properties of lightly Ta-doped SnO (SnTaO, TTO) thin films epitaxially grown on TiO (001) substrates by pulsed laser deposition. The carrier density (n) of the TTO films was systematically controlled by x.

Direct Observation of Magnetization Reversal by Electric Field at Room Temperature in Co-Substituted Bismuth Ferrite Thin Film.

Using the electric field to manipulate the magnetization of materials is a potential way of making low-power-consumption nonvolatile magnetic memory devices. Despite concentrated effort in the last 15 years on magnetic multilayers and magnetoelectric multiferroic thin films, there has been no report on the reversal of out-of-plane magnetization by an electric field at room temperature without the aid of an electric current. Here, we report direct observation of out-of-plane magnetization reversal at room temperature by magnetic force microscopy after electric polarization switching of cobalt-substituted bismuth ferrite thin film grown on (110)-oriented GdScO substrate.

Electric-Field-Induced Reorientation of the Magnetic Easy Plane in a Co-Substituted BiFeO Single Crystal.

Single crystals of BiFeCoO and BiFeMnCoO, room temperature ferroelectric ferromagnets, were successfully grown by a flux method at a high pressure of 3 GPa. Remanent magnetization measurements along 18 crystallographic directions revealed the existence of a magnetic easy plane perpendicular to the electric polarization. Reorientation of the magnetic easy plane occurred in connection with 71° ferroelectric switching by applying an electric field.