Multiferroics. Magnetoelectric domain control in multiferroic TbMnO₃.

The manipulation of domains by external fields in ferroic materials is of major interest for applications. In multiferroics with strongly coupled magnetic and electric order, however, the magnetoelectric coupling on the level of the domains is largely unexplored. We investigated the field-induced domain dynamics of TbMnO3 in the multiferroic ground state and across a first-order spin-flop transition.

Ferroelectric glycine silver nitrate: a single-crystal neutron diffraction study.

Protonated crystals of glycine silver nitrate (C4H10Ag2N4O10) undergo a displacive kind of structural phase transition to a ferroelectric phase at 218 K. Glycine silver nitrate (GSN) is a light-sensitive crystal. Single-crystal X-ray diffraction investigations are difficult to perform on these crystals due to the problem of crystal deterioration on prolonged exposure to X-rays.

Magnetic structure of CuCrO₂: a single crystal neutron diffraction study.

This paper presents results of a recent study of multiferroic CuCrO(2) by means of single crystal neutron diffraction. This system has two close magnetic phase transitions at T(N) = 24.2 K and T(mf) = 23.

Novel features of the α-β phase transition in quartz-type FePO₄ as evidenced by x-ray diffraction and lattice dynamics.

We present novel results on the mechanism of the α-β structural phase transition (STP) occurring in FePO₄. High accuracy x-ray diffraction experiments followed by a structural analysis provide us with precise information on the thermal disorder change on different atomic sites. The data are analysed in the light of lattice dynamics simulation results.

Signature of checkerboard fluctuations in the phonon spectra of a possible polaronic metal La1.2Sr1.8Mn2O7.

Charge carriers in low-doped semiconductors may distort the atomic lattice around them and through this interaction form so-called small polarons. High carrier concentrations on the other hand can lead to short-range ordered polarons (large polarons) and even to a long-range charge and orbital order. These ordered systems should be insulating with a large electrical resistivity.