Phase stability and thermal expansion of ZnO solid solutions with 3d transition metal oxides synthesized at high pressure

Chemical Pressure Effect on the Stabilization of Rock-Salt ZnO—Lin−2MeOn−1 Solid Solutions Synthesized at High Pressure

“…The unit for V(T) and V 0 is Å 3 ; the units for α 1 and α 2 are K −1 and K −2 , respectively. The quadratic dependence of V(T) has been previously observed for ZnO-rich cubic solid solutions in other Li-containing systems [9,10,15], and α 1 and α 2 are close to the previously reported values [15]. The temperature dependencies of full width at half maximum (FWHM) for the 200 line (100% intensity) of rs-(LiScO 2 ) 1−x (ZnO) x solid solutions are shown in Figure 3b.…”

“…For x < 0.6, the dependence of the thermal expansion coefficient on the composition is practically absent (Table 3, Figure S4), whereas for x ≥ 0.6, a tendency for its decrease with increasing zinc oxide content is observed. Note that extrapolation to 100% ZnO content (rs-ZnO) gives a value close to that previously reported by us [10]. Thus, for the first time, we have synthesized cubic ZnO-Li 2 TiO 3 solid solutions in a wide concentration range (0.1 ≤ x ≤ 0.8), which are characterized by high thermal stability.…”

“…The rock-salt structure, in contrast to the wurtzite one, allows the synthesis of ZnO solid solutions with a wide variety of cations. Previously, for Zn 2+ ← Me 2+ substitution, isovalent cations (Me 2+ = Mg 2+ , Ni 2+ , Fe 2+ , Co 2+ , and Mn 2+ ) with a tendency to octahedral environments were selected, which significantly affected the thermal stability of the formed solid solutions [8][9][10][11][12][13][14]. The most stable solid solutions with high ZnO content (up to 80 mol%) were those with magnesium and nickel oxides.…”

“…The most stable solid solutions with high ZnO content (up to 80 mol%) were those with magnesium and nickel oxides. For example, the cubic Ni 0.2 Zn 0.8 O is stable up to 970 K, whereas the cubic Co 0.3 Zn 0.7 O is stable only up to 670 K. The decomposition products are usually mixtures of two solid solutions, one with a cubic structure and another with a wurtzite structure [8][9][10].…”

High-Pressure Synthesis of Cubic ZnO and Its Solid Solutions with MgO Doped with Li, Na, and K

“…However, it is clear that rs-Mg x Zn 1−x O alloys are composed of more than one phase with different optical properties, despite their apparent homogeneity according to the visual analysis of the XRD data. For example, a similar situation has recently been demonstrated for related rs-Ni x Zn 1−x O solid solutions which show distinct structural features in the ZnO-enriched region [38,39]. There, nonlinear behavior of thermal expansion coefficients is evident and may indicate that the solid solution in question is nonequilibrium.…”