BiFeO3 ceramics were investigated by means of infrared reflectivity and time domain THz transmission spectroscopy at temperatures 20 -950 K and the magnetodielectric effect was studied at 10 -300 K with the magnetic field up to 9 T. Below 175 K, the sum of polar phonon contributions into the permittivity corresponds to the value of measured permittivity below 1 MHz. At higher temperatures, a giant low-frequency permittivity was observed, obviously due to the enhanced conductivity and possible Maxwell-Wagner contribution. Above 200 K the observed magnetodielectric effect is caused essentially through the combination of magnetoresistance and the Maxwell-Wagner effect, as recently predicted by Catalan (Appl. Phys. Lett. 88, 102902 (2006)). Since the magnetodielectric effect does not occur due to a coupling of polarization and magnetization as expected in magnetoferroelectrics, we call it improper magnetodielectric effect. Below 175 K the magnetodielectric effect is by several orders of magnitude lower due to the decreased conductivity. Several phonons exhibit gradual softening with increasing temperature, which explains the previously observed highfrequency permittivity increase on heating. The observed non-complete phonon softening seems to be the consequence of the first-order nature of the ferroelectric transition.

The hydrolysis of Ln(ClO4)3 in the presence of acetate leads to the assembly of the three largest known lanthanide-exclusive cluster complexes, [Nd104(ClO4)6(CH3COO)60(μ3-OH)168(μ4-O)30(H2O)112]·(ClO4)18·(CH3CH2OH)8·xH2O (1, x ≈ 158) and [Ln104(ClO4)6(CH3COO)56(μ3-OH)168(μ4-O)30(H2O)112]·(ClO4)22·(CH3CH2OH)2·xH2O (2, Ln = Nd; 3, Ln = Gd; x ≈ 140). The structure of the common 104-lanthanide core, abbreviated as Ln8@Ln48@Ln24@Ln24, features a four-shell arrangement of the metal atoms contained in an innermost cube (a Platonic solid) and, moving outward, three Archimedean solids: a truncated cuboctahedron, a truncated octahedron, and a rhombicuboctahedron. The magnetic entropy change of ΔS(m) = 46.9 J kg(-1) K(-1) at 2 K for ΔH = 7 T in the case of the Gd104 cluster is the largest among previously known lanthanide-exclusive cluster compounds.

The magnetocaloric effect of orthorhombic Gd(OH)CO3 has been experimentally studied, which exhibits −ΔSm up to 66.4 J kg−1 K−1 (355 mJ cm−3 K−1) for ΔH = 7 T and T = 1.8 K.

The use of paramagnetic molecules as cryogenic coolants usually requires relatively large fields to obtain a practical cooling effect. Thus, research for magnetic molecular materials with larger MCEs in fields of ≤ 2 T is the central science. In this work, the crystal structure, magnetic susceptibility and isothermal magnetization for inorganic framework material GdF 3 were measured, and the isothermal entropy change was evaluated up to 9 T. Thanks to combination of the large isotropic spin of Gd 3+ , the dense structure and the weak ferromagnetic interaction, an extremely large -∆S m for GdF 3 was observed up to 528 mJ cm -3 K -1 for ∆µ 0 H = 9 T, proving itself to be an exceptional cryogenic magnetic coolant.The magnetocaloric effect of a inorganic framework material with repeating unit of GdF 3 has been experimentally studied using isothermal magnetization and heat capacity measurements. The maximum entropy change -∆S max reaches 74.8 J kg -1 K -1 or 528 mJ cm -3 K -1 for ∆H = 9 T and T = 1.8 K.

We describe the first-principles design and subsequent synthesis of a new material with the specific functionalities required for a solid-state-based search for the permanent electric dipole moment of the electron. We show computationally that perovskite-structure europium barium titanate should exhibit the required large and pressure-dependent ferroelectric polarization, local magnetic moments and absence of magnetic ordering at liquid-helium temperature. Subsequent synthesis and characterization of Eu(0.5)Ba(0.5)TiO(3) ceramics confirm the predicted desirable properties.

The comprehensive study reported herein provides compelling evidence that anion templates are the main driving force in the formation of two novel nanoscale lanthanide hydroxide clusters, {Gd38(ClO4)6} (1) and {Gd48Cl2(NO3)} (2), characterized by single-crystal X-ray crystallography, infrared spectroscopy, and magnetic measurements. {Gd38(ClO4)6}, encapsulating six ClO4(-) ions, features a cage core composed of twelve vertex-sharing {Gd4} tetrahedrons and one Gd⋅⋅⋅Gd pillar. When Cl(-) and NO3(-) were incorporated in the reaction instead of ClO4(-), {Gd48Cl2(NO3)} is obtained with a barrel shape constituted by twelve vertex-sharing {Gd4} tetrahedrons and six {Gd5} pyramids. What is more, the cage-like {Gd38} can be dynamically converted into the barrel-shaped {Gd48} upon Cl(-) and NO3(-) stimulus. To our knowledge, it is the first time that the linear M-O-M' fashion and the unique μ8-ClO4(-) mode have been crystallized in pure lanthanide complex, and complex 2 represents the largest gadolinium cluster. Both of the complexes display large magnetocaloric effect in units of J kg(-1) K(-1) and mJ cm(-3) K(-1) on account of the weak antiferromagnetic exchange, the high N(Gd)/M(W) ratio (magnetic density), and the relatively compact crystal lattice (mass density).

Water is characterized by large molecular electric dipole moments and strong interactions between molecules; however, hydrogen bonds screen the dipole–dipole coupling and suppress the ferroelectric order. The situation changes drastically when water is confined: in this case ordering of the molecular dipoles has been predicted, but never unambiguously detected experimentally. In the present study we place separate H2O molecules in the structural channels of a beryl single crystal so that they are located far enough to prevent hydrogen bonding, but close enough to keep the dipole–dipole interaction, resulting in incipient ferroelectricity in the water molecular subsystem. We observe a ferroelectric soft mode that causes Curie–Weiss behaviour of the static permittivity, which saturates below 10 K due to quantum fluctuations. The ferroelectricity of water molecules may play a key role in the functioning of biological systems and find applications in fuel and memory cells, light emitters and other nanoscale electronic devices.

We report on single crystal growth and crystallographic parameters results of Ce 2 PdIn 8 , Ce 3 PdIn 11, Ce 2 PtIn 8 and Ce 3 PtIn 11 . The Pt-systems Ce 2 PtIn 8 and Ce 3 PtIn 11 are synthesized for the first time. All these compounds are member of the Ce n T m In 3n+2m (n = 1, 2,..; m = 1, 2,.. and T = transition metal) to which the extensively studied heavy fermion superconductor CeCoIn 5 belongs. Single crystals have been grown by In self-flux method. Differential scanning calorimetry studies were used to derive optimal growth conditions. Evidently, the maximum growth conditions for these materials should not exceed 750 °C. Single crystal x-ray data show that Ce 2 TIn 8 compounds crystallize in the tetragonal Ho 2 CoGa 8 phase (space group P4/mmm) with lattice parameters a =4.6898(3) Å and c =12.1490(8) Å for the Pt-based one (Pd: a = 4.6881(4) Å and c = 12.2031(8) Å). The Ce 3 TIn 11 compounds adopt the Ce 3 PdIn 11 structure with a = 4.6874(4) Å and c = 16.8422(12) Å for the Pt-based one (Pd: a = 4.6896 Å and c = 16.891 Å). Specific heat experiments on Ce 3 PtIn 11 and Ce 3 PdIn 11 have revealed that both compounds undergo two successive magnetic transitions at T 1 ~ 2.2 K followed by T N ~ 2.0 K and T 1 ~ 1.7 K and T N ~ 1.5 K, respectively. Additionally, both compounds exhibit enhanced Sommerfeld coefficients yielding γ Pt = 0.300 J/mol K 2 Ce (γ Pd = 0.290 J/mol K 2 Ce), hence qualifying them as heavy fermion materials.