Ambient pressure synthesis of Eu3+ doped δ-BiB3O6 by seed-assisted high temperature solid state reactions

A high level of Eu³⁺ (7 atom%) was doped successfully, suggesting the possible single crystal growth of bi-functional RE³⁺-doped δ-BiB₃O₆.

Giant magnetoelectric effects in pseudo 1-3 heterostructure films with FeGa nanocluster-assembled micron-scale discs embedded into Bi5Ti3FeO15 matrices

Nanocluster-assembled FeGa micron-scale discs prepared by low-energy cluster beam deposition were embedded into Bi5Ti3FeO15 matrices to form pseudo 1-3 heterostructure films. The microstructures and multiferroic properties were investigated. Good ferroelectric, piezoelectric, and ferromagnetic properties and giant magnetoelectric effects are achieved for the heterostructure films, which is ascribed to the depression of the clamped effect from the hard substrate for such pseudo 1-3 structures and the multi-interface coupling between the large magnetostrictive coefficient of FeGa micron-scale discs and the high piezoelectric coefficient of the circle surrounding the Bi5Ti3FeO15 matrices. Such a strong interface strain coupling between the micron discs and the inhomogeneously multiferroic matrices induces obvious magnetoelectric coupling behaviors. Besides, the interaction between the ferroelectric domains and the spin orders in the multiferroic matrices also contributes to the magnetoelectric output. The present work provides a potential way to fabricate clamped-free magnetoelectric films for microdevice applications.

Photoacoustic trace detection of gases at the parts-per-quadrillion level with a moving optical grating

The amplitude of the photoacoustic effect for an optical source moving at the sound speed in a one-dimensional geometry increases linearly in time without bound in the linear acoustic regime. Here, use of this principle is described for trace detection of gases, using two frequency-shifted beams from a CO₂ laser directed at an angle to each other to give optical fringes that move at the sound speed in a cavity with a longitudinal resonance. The photoacoustic signal is detected with a high-[Formula: see text], piezoelectric crystal with a resonance on the order of [Formula: see text] kHz. The photoacoustic cell has a design analogous to a hemispherical laser resonator and can be adjusted to have a longitudinal resonance to match that of the detector crystal. The grating frequency, the length of the resonator, and the crystal must all have matched frequencies; thus, three resonances are used to advantage to produce sensitivity that extends to the parts-per-quadrillion level.