Solid‐state sintering has been used to prepare the perovskite BaZr0.9Sc0.1O3−δ. Analysis of X‐ray powder diffraction data shows that an increase of the unit cell parameter, a, was observed after deuteration. Rietveld analysis of room‐temperature neutron powder diffraction data confirmed cubic symmetry (space group Pm‐3m). Dynamic thermogravimetric analysis indicates that the hydration process occurs below 335°C and approximately 58% of the theoretical number of protonic defects can be filled. The presence of protons/deutrons is seen from the strong O–H/O–D stretch band in the infrared spectrum of the hydrated/deuterated samples. The proton conductivity of a prehydrated sample was investigated under dry and wet Ar atmospheres.

We present an extensive experimental and theoretical study on the low-temperature magnetic properties of the monoclinic anhydrous alum compound BaMo(PO4)2. The magnetic susceptibility reveals strong antiferromagnetic interactions θCW = −167 K and long-range magnetic order at TN = 22 K, in agreement with a recent report. Powder neutron diffraction furthermore shows that the order is collinear, with the moments near the ac plane. Neutron spectroscopy reveals a large excitation gap ∆ = 15 meV in the low-temperature ordered phase, suggesting a much larger easyaxis spin anisotropy than anticipated. However, the large anisotropy justifies the relatively high ordered moment, Néel temperature, and collinear order observed experimentally, and is furthermore reproduced in a first principles calculations using a new computational scheme. We therefore propose BaMo(PO4)2 to host S = 1 antiferromagnetic chains with large easy-axis anisotropy, which has been theoretically predicted to realize novel excitation continua. arXiv:1912.03969v1 [cond-mat.str-el]

A wet chemical route has been used to synthesize the oxygen deficient perovskite BaZr 0.5 Yb 0.5 O 3−␦ . Analysis of X-ray powder diffraction data showed that both dried and hydrated samples adopt cubic crystal structures of space group Pm3m. Dynamic thermogravimetric analysis showed a significant mass loss for the hydrated sample compared to the dried sample, indicating that ϳ28% of the oxygen vacancies are filled by protonic defects. The strong O-H stretch band, 2500-3500 cm −1 , in the IR absorbance spectrum also clearly manifests the presence of significant levels of protons in the hydrated material. Proton conductivity was investigated on prehydrated ͑under dry Ar͒ and as-prepared ͑under wet Ar͒ samples. The heating cycle of the prehydrated sample showed higher proton conductivity compared to the cooling cycle, especially in the intermediate temperature range ͑150-550°C͒. Finally, comparison with data for BaZr 0.9 Yb 0.1 O 3−␦ revealed that the more heavily doped sample showed higher proton conductivity compared to the more lightly doped sample.Increasing awareness of environmental factors coupled to a limited supply of energy resources has forced society to search for alternative clean energy sources. Fuel cells offer the possibility of directly converting chemical energy to electrical energy in an environmentally sustainable way. Low-temperature ͑T Ͻ 100°C͒ fuel cells, such as a polymer electrolyte fuel cell, where Nafion ͑perfluo-rosulfonic polymer͒ is used as the electrolyte, require expensive platinum catalysts. The high operating temperature of fuel cells based on oxide ion electrolytes leads to problems with material degradation and long start-up times. Therefore, fuel cells operating in an intermediate temperature range ͑200-500°C͒ are desirable alternatives.Generally, proton conducting materials are used as the electrolyte for intermediate temperature fuel cell ͑ITFC͒ due to their higher conductivity compared to oxide ion conducting materials in this temperature range. 1 Successive investigation and literature data compiled by Norby 2 show the presence of a "gap," within the intermediate temperature range, in which no electrolyte materials show sufficiently high proton conductivity. Low proton conductivity in the electrolyte materials has subdued the development of state-of-the-art ITFC. This motivates significant research efforts aimed at understanding and improving proton conducting properties in this key temperature range.Acceptor-doped alkaline earth perovskites are well-known proton-conducting ceramic materials. For example, Y-doped BaZrO 3 or BaCeO 3 are already known as very good proton conductors, reaching conductivities of ϳ10 −2 to 10 −3 S cm −1 at temperatures of ϳ300 to 600°C. 1,3-6 Cerates generally suffer from chemical instability under CO 2 containing atmospheres, readily forming alkaline earth carbonates according to 7,8 BaCeO 3 + CO 2 → BaCO 3 + CeO 2 ͓1͔In contrast, BaZrO 3 exhibits excellent stability under CO 2 . 8 Moreover, it has recently been recognized that 10 mol % Y-doped B...