Resilience of the Aurivillius structure upon La and Cr doping in a BiTiFeO multiferroic.

Combining the experimental techniques of high-resolution X-ray diffraction, magnetometry, specific heat measurement, and X-ray photoelectron, Raman and dielectric spectroscopy techniques, we have studied the influence of La and Cr doping on the crystal structure and magnetism of the room temperature Aurivillius multiferroic BiTiFeO by investigating the physical properties of (BiLa)TiFeO and BiTi (FeCr)O. The parent (BiTiFeO) and the doped ((BiLa)TiFeO and BiTi(FeCr)O) compounds crystallize in the 2 space group, which is confirmed through our analysis of high-resolution synchrotron X-ray diffraction data obtained on phase-pure polycrystalline powders. We determined the oxidation states of the metal atoms in the studied compounds as Fe, Ti, Cr, and La through the analysis of X-ray photoelectron spectroscopy data.

Unusual critical behavior of Griffiths ferromagnet HoNiMnOat magnetic phase transition.

The critical behavior at the ferromagnetic to paramagnetic phase transition of a Griffiths ferromagnet, HoNiMnO, is studied using modified Arrott plot, Kouvel-Fisher, and critical isotherm analysis. Here, we report a second-order phase transition and conclude from the estimated critical exponents that it is unusual and do not belong to conventional universality classes. However, they obey scaling relationships, which indicates the renormalization of interactions around the phase transition temperature.

Record-high thermal stability achieved in a novel single-component all-organic ferroelectric crystal exhibiting polymorphism.

Traditionally, lead and heavy metal containing inorganic oxides dominate the area of ferroelectricity. Although, recently, lightweight non-toxic organic ferroelectrics have emerged as excellent alternatives, achieving higher temperature up to which the ferroelectric phase can persist has remained a challenge. Moreover, only a few of those are single-component molecular ferroelectrics and were discovered upon revisiting their crystal structures.

Electronic structure of PrMnNiO from x-ray photoemission, absorption and density functional theory.

The electronic structure of double perovskite PrMnNiO was studied using core x-ray photoelectron spectroscopy and x-ray absorption spectroscopy. The 2p x-ray absorption spectra show that Mn and Ni are in 4+  and 2+  states respectively. Based on charge transfer multiplet analysis of the 2p XPS spectra of both ions, we find charge transfer energies [Formula: see text] of 3.

Antiphase boundary in antiferromagnetic multiferroic LuMnFeO: anomalous ferromagnetism, exchange bias effect and large vertical hysteretic shift.

The emergence of exchange bias effect in FeO thin films has been since attributed to the presence of anti phase boundary (APB) growth defects despite lack of direct experimental evidence. In the present report, APB induced anomalous weak ferromagnetism and exchange bias property of single-phase antiferromagnetic (AFM) system LuMnFeO (LMFO) is discussed and Fe Mössbauer spectroscopy and high resolution transmission electron microscopy (HRTEM) measurements are used to probe the origin of the observed effect. In addition to the sextet component corresponding to the long range AFM ordering, the measured Mössbauer spectra reveal the presence of a small component (10%-12%) near zero velocity with unusually small internal field.

Disordered ferromagnetism in HoNiMnO double perovskite.

Magnetic and dielectric properties of the double perovskite HoNiMnO are reported. The compound is synthesized by nitrate route and is found to crystallize in monoclinic P2/n space group. Lattice parameters obtained by refining powder x-ray diffraction data are; a  =  5.

Evolution of Jahn-Teller distortion, transport and dielectric properties with doping in perovskite NdFe1-xMnxO3 (0 ≤ x ≤ 1) compounds.

We have carried out dielectric and transport measurements in NdFe1-xMnxO3 (0 ≤ x ≤ 1) series of compounds and studied the variation of activation energy due to a change in Mn concentration. Despite similar ionic radii in Mn(3+) and Fe(3+), large variation is observed in the lattice parameters and a crossover from dynamic to static Jahn-Teller distortion is discernible. The Fe/Mn-O-Fe/Mn bond angle on the ab plane shows an anomalous change with doping.

Bulk-Induced 1/f Noise at the Surface of Three-Dimensional Topological Insulators.

Slow intrinsic fluctuations of resistance, also known as the flicker noise or 1/f-noise, in the surface transport of strong topological insulators (TIs) is a poorly understood phenomenon. Here, we have systematically explored the 1/f-noise in field-effect transistors (FET) of mechanically exfoliated Bi1.6Sb0.

Interplay of structure, magnetism, and superconductivity in Se substituted iron telluride with excess Fe.

We investigated the evolution of the temperature-composition phase diagram of Fe(1+y)Te upon Se substitution. In particular, the effect of Se substitution on the two-step, coupled magneto-structural transition in Fe(1+y)Te single crystals is investigated. To this end, the nominal Fe excess was kept at y = 0.

Dielectric and Raman investigations of structural phase transitions in (C2H5NH3)2CdCl4.

Temperature-dependent Raman and dielectric measurements have been carried out on (C2H5NH3)2CdCl4 single crystals. Raman studies reveal the presence of two structural phase transitions below room temperature at 216 K and 114 K. The phase transitions are marked by anomalies in temperature dependence of wave-number and full width half maximum (FWHM) of several vibrational modes.

Correspondence between neutron depolarization and higher order magnetic susceptibility to investigate ferromagnetic clusters in phase separated systems.

It is a tough task to distinguish a short-range ferromagnetically correlated cluster-glass phase from a canonical spin-glass-like phase in many magnetic oxide systems using conventional magnetometry measurements. As a case study, we investigate the magnetic ground state of La0.85Sr0.

Memory effect in Dy0.5Sr0.5MnO3 single crystals.

We have performed a series of magnetic aging experiments on single crystals of Dy(0.5)Sr(0.5)MnO(3).

An investigation of first-order transition across charge ordered and ferromagnetic phases in Gd(0.5)Sr(0.5)MnO3 single crystals by magnetic and magnetotransport studies.

Gadolinium strontium manganite single crystals of the composition Gd(0.5)Sr(0.5)MnO(3) were grown using the optical float zone method.

Phase transitions and rare-earth magnetism in hexagonal and orthorhombic DyMnO(3) single crystals.

The floating-zone method with different growth ambiences has been used to selectively obtain hexagonal or orthorhombic DyMnO(3) single crystals. The crystals were characterized by x-ray powder diffraction of ground specimens and a structure refinement as well as electron diffraction. We report magnetic susceptibility, magnetization and specific heat studies of this multiferroic compound in both the hexagonal and the orthorhombic structure.

Development of a versatile high temperature top seeded solution growth unit for growing cesium lithium borate crystals.

The design and fabrication of a state of the art high temperature top seeded solution growth (HTTSSG) unit with seed and crucible rotation options is discussed. Crystals from solid solutions of high viscosity could be grown using the setup. The fabricated setup is used to grow high optical quality single crystals of cesium lithium borate with dimensions 50x40x40 mm(3) for frequency conversion of ir to UV laser through harmonic generation.

Investigations on the spin-glass state in Dy(0.5)Sr(0.5)MnO(3) single crystals through structural, magnetic and thermal properties.

Single crystals of Dy(0.5)Sr(0.5)MnO(3) are grown using the optical floating zone technique, and their structural, magnetic, transport and thermal properties have been investigated.

Influence of Nd:Zn codoping in near-stoichiometric lithium niobate.

Near-stoichiometric lithium niobate (SLN) crystals doped with up to 1.6 mol % Zn and codoped with various Nd concentrations in the melt (0.2, 0.