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Masuno, Atsunobu*; Munakata, Sae*; Okamoto, Yoshihiro; Yaji, Toyonari*; Kosugi, Yoshihisa*; Shimakawa, Yuichi*
Inorganic Chemistry, 63(12), p.5701 - 5708, 2024/03
Times Cited Count:1 Percentile:64.06(Chemistry, Inorganic & Nuclear)Transparent and brown LaO
-MoO
binary glasses were prepared in bulk form using a levitation technique. The glass-forming range was limited, with the primary composition being approximately 25 mol% La
O
. This glass exhibited a clear crystallization at 546
C, while determining its glass transition temperature was difficult. Notably, despite its amorphous nature, the glass possessed a density and packing density comparable to those of crystalline La
Mo
O
. X-ray absorption fine structure and Raman scattering analyses revealed that the glass structure closely resembles La
Mo
O
due to the presence of isolated MoO
units, whereas disordered atomic arrangement around La atoms was confirmed. The glass demonstrated transparency ranging from 378 to 5500 nm, and the refractive index at 1.0
m was estimated to be 2.0. The optical bandgap energy was 3.46 eV, which was slightly smaller than that of La
Mo
O
. Additionally, the glass displayed a transparent region ranging from 6.5 to 8.0
m. This occurrence results from the decreased diversity of MoO
units and connectivity of Mo-O-Mo, which resulted in the reduced overlap of multiphonon absorption. This glass formation, with its departure from conventional glass-forming rules, resulted in distinctive glasses with crystal-like atomic arrangements.
Kosugi, Yoshihisa*; Goto, Matato*; Tan, Z.*; Kan, Daisuke*; Isobe, Masahiko*; Yoshii, Kenji; Mizumaki, Masaichiro*; Fujita, Asaya*; Takagi, Hidenori*; Shimakawa, Yuichi*
Scientific Reports (Internet), 11(1), p.12682_1 - 12682_8, 2021/06
Times Cited Count:7 Percentile:40.16(Multidisciplinary Sciences)Caloric effects of solids provide more efficient and environment-friendly innovative refrigeration systems compared to the widely-used conventional vapor compressive cooling systems. Exploring novel caloric materials is challenging but critically important in developing future technologies. Here we discovered that the quadruple perovskite structure ferrimagnet BiCuCr
O
shows a large multicaloric effect at the first-order charge transition occurred around 190 K. Large latent heat and the corresponding isothermal entropy changes 28.2 J K
kg
can be fully utilized by applying both magnetic fields (magnetocaloric effect) and pressure (barocaloric effect). Adiabatic temperature changes reach 3.9 K for the 50 kOe magnetic field and 4.8 K for the 4.9 kbar pressure, and thus highly efficient thermal controls are achieved by multiple ways.