Tuning the monoclinic-to-orthorhombic phase transition temperature of Fe₂Mo₃O₁₂by substitutional co-incorporation of Zr⁴⁺and Mg²⁺

Abstract

Abstract

Phase transition and near-zero thermal expansion in ZrFeMo2VO12

“…3d illustrates the changes of Raman bands by multi-peak fit. The Raman band at about 1000 cm -1 is characteristic for monoclinic structure [15,16,[23][24][25] which can be seen for the spectra from 134 K to 298 K but disappears at 314 K. It is obvious that there is a phase transition at 298 ~ 314 K, which agrees well with the result of variable-temperature XRD. .93 × 10 −6 K −1 , −2.27 × 10 −6 K −1 , −3.62 × 10 −6 K −1 for a, b and c axes, respectively.…”

“…Furthermore, the thermal expansion coefficient (TEC) of A 2 M 3 O 12 can be adjusted by varying the type and content of the substitution of cation, which provides a possible way to prepare materials with adjustable TEC, especially those with zero TEC [11]. Related reports include (Al 2x (HfMg) 1-x )(WO 4 ) 3 [12], In(HfMg) 0.5 Mo 3 O 12 [13] (x = 1.7) were reported to be 425 K, 385 K, below 103 K, below103 K, respectively [13][14][15][16].…”

Near-zero thermal expansion of In 2(1− x ) (HfMg) x Mo 3 O 12 with tailored phase transition

“…The peak located at about 995 cm −1 originates from the monoclinic structure. [27,35,36] This Raman band decays gradually with increasing the content of (HfMg) 6+ and disappears finally at about x = 0.85, suggesting a transition from the monoclinic to orthorhombic phase occurring at this composition ratio. x/ 995 An endothermic peak appears at 616 K when x = 0, indicating the monoclinic-to-orthorhombic phase transition occurring at this temperature.…”

“…[22,31] According to previous reports, the Raman spectra are sensitive to the monoclinic-to-orthorhombic phase transition. [27,35,36] In order to confirm the phase transition after the introduction of (HfMg) 6+ , Raman spectra of the solid solutions of In 2(1−x) (HfMg) x Mo 3 O 12 are measured and shown in Fig. 2.…”

Near-Zero Thermal Expansion and Phase Transitions in HfMg1−xZnxMo3O12

“…It is reasonable to conclude that HfMg 1− x Zn x Mo 3 O 12 for x ≤ 0.4 crystallized in an orthorhombic structure. Nevertheless, some subtle changes are observed for x = 0.5, such as the weak peak appearing at about 25.6° which is characteristic for a monoclinic structure (Song et al, 2014b; Ge et al, 2016a) of ABMo 3 O 12 . HfMg 0.5 Zn 0.5 Mo 3 O 12 at RT is thus identified as a monoclinic structure.…”