Hall Effect and Conductivity in the Neodymium–Hydrogen System

Influence of Crystal Structure, Encapsulation, and Annealing on Photochromism in Nd Oxyhydride Thin Films

“…Thin films of NdH 3–2 x O x deposited between p dep = 0.3–0.9 Pa result in various optical properties upon air oxidation, similar to our previous work using other rare-earth cations (RE = Sc, Y, Gd, Er, Dy). − Films deposited at low pressures ( p dep = 0.3–0.5 Pa) are opaque (Figure a), meaning low average transmittance (Figure b), and have no optical band gap, suggesting that they largely maintain the as-deposited NdH 1.9+δ composition. − …”

“…This film could be very minimally oxidized, yet still maintaining the metallic properties of as-deposited NdH 1.9+δ . 13 , 14 , 16 , 17 …”

“…This film could be very minimally oxidized, yet still maintaining the metallic properties of as-deposited NdH 1.9+δ . 13,14,16,17 However, films deposited at and above a critical deposition pressure 3 (p dep * ∼ 0.6 Pa) are more transparent (Figure 2a,b) and have an optical band gap (Figure 2c). This is expected because, as the deposition pressure increases, thin films produced by sputtering are progressively more porous.…”

“…The dihydride phase of the films deposited at p dep < 0.6 Pa is further confirmed by the small transparency window observable in the transmission spectrum (Figure S7), typical of RE dihydrides. − ,, The transmission spectrum for the 0.5 Pa sample, however, shows a larger transparency window, extending toward longer wavelengths. This film could be very minimally oxidized, yet still maintaining the metallic properties of as-deposited NdH 1.9+δ . ,,, …”

Low temperature specific heats of the dihydrides of the light rare earth metals

“…Recent positron annihilation rates studies on lanthanum hydrides were interpreted in terms of the hydridic model [31]. The negative sign of the Seebeck coefficient [32] and a preliminary positron annihilation study [33] dymium 139, 401 as well as the reported Hall coefficients for neodymium hydride [41] were interpreted in terms of a protonic model in contradiction to the magnetic susceptibility measurements [42,43].…”