Unexpected luminescence of Cr5+ and Cr3+ ions in ZrSiO4 zircon crystals

Low temperature synthesis of green submicro Cr‐ZrSiO4 ceramic pigments by solid‐state method

“…As the temperature rises to 1400°C, it can be obviously observed in Figure 2D that the primary crystalline phases of all samples are ZrSiO 4 structure, but not phase associated with chromium. One possible charge compensation mechanism is the double substitution of Cr 3+ /Cr 5+ in the two Zr 4+ /Si 4+ neighborhoods of the zircon lattice, which is consistent with the conclusion that Cr‐ZrSiO 4 is an ion‐substituted pigments in the literature 26 . Thus, the final products of Cr‐ZrSiO 4 without Li 2 CO 3 can be considered to be completely formed at 1400°C for 2 h. Obviously, the synthesis temperature of Cr‐ZrSiO 4 at 1400°C is too high for practical application, so the synthesis temperature needs to be lowered further.…”

Magnetic excitations of the gapped quantum spin dimer antiferromagnetSr3Cr2O8

“…The value of C corresponds to an effective moment of 1.8(1)µ B /Cr 5+ , which is close to the value of 1.72µ B expected for spin-1/2 Cr 5+ ions assuming a g-factor of 1.98 taken from a previous EPR measurement 22 . The values obtained from fitting the susceptibility data with the field parallel to the c h axis are:…”

“…The fitted parameters for the data with the field perpendicular to the c h axis are χ 0 = 2.32(5) × 10 −4 cm 3 /mol, C imp = 0.0465(5) cm 3 K/mol, θ imp = −15.7(2) K, C = 0.875(2) cm 3 K/mol, J 0 = 5.517(2) meV, J ′ = 1.22 (5) meV. The value of C corresponds to an effective moment of 1.8(1)µ B /Cr 5+ , which is close to the value of 1.72µ B expected for spin-1/2 Cr 5+ ions assuming a g-factor of 1.98 taken from a previous EPR measurement 22 . The values obtained from fitting the susceptibility data with the field parallel to the c h axis are:…”

Nanopowders Y1−yNdyV1−xCrxO4 with y=0 and 1; x=0, 0.1, 0.2 and 0.5 synthesized by a sol–gel process. Relationship between morphological characteristics and optical properties

“…In YVO 4 :Cr 5 þ and YPO 4 :Cr 5 þ materials emission lines between 1200 and 1590 nm have been reported [42]. Generally, these emissions are detected at low temperature of the samples (about 15 K), although, in some cases, it may be observed at room temperature, as in ZrSiO 4 :Cr [54], where luminescence emission was observed near 1200 nm. Notice that Cr 5 þ ion emission could not be detected in our samples using the present experimental setup.…”