EPR lineshape studies of low-temperature vanadium 3d1 polaron dynamics in the 70V2O5-30P2O5 binary glass

Sol–gel synthesis and characterization of xCuO–(1 − x)Bi 2 O 3 (0.15 ≤ x ≤ 0.55) glasses by magnetic and spectral studies

“…These properties arise from the thermally assisted hopping of Cu 2+ (3d 9 ) electron, which is essentially a 'small polaron' [7], from a lower valent Cu + (3d 10 ) site to a higher valent Cu 2+ (3d 9 ) site. It is reported in literature that the thermally assisted hopping rate of small polaron has marked effect on the electron paramagnetic resonance (EPR) lineshapes [8]; and even at a very low temperature, the thermal hopping rate of small polaron is fast enough to smear out the electron spin-nuclear spin hyperfine interaction to give rise to motionally narrowed EPR lineshapes [9]. In such a situation, it is known that the temperature dependent derivative EPR peak-topeak linewidth of the glass is a measure of the activation energy of hopping [8], E a , of the small polaron.…”

“…One of the most powerful and sensitive experimental technique is EPR spectroscopy for determining the paramagnetic 'site' symmetry and the coordination geometry around Cu 2+ (3d 9 ) paramagnetic site, in terms of molecular orbital pictures [10]. EPR spectroscopy is also an indispensable technique to study the temperature dependent EPR lineshape modulation, due to thermally assisted hopping of the small polarons [9] in glasses containing mixed-valence TM ions.…”

“…EPR spectroscopy is also an indispensable technique to study the temperature dependent EPR lineshape modulation, due to thermally assisted hopping of the small polarons [9] in glasses containing mixed-valence TM ions. The outcome of such EPR studies, also throws light on the optical absorptions by these systems [4].…”

“…Among the host of mixed-valence TM ions containing oxide glasses, growing attention has been focused onto CuO-and Bi 2 O 3 -containing glasses, because of their interesting magnetic [2,3], optical [4] and semiconducting properties [5,6]. These properties arise from the thermally assisted hopping of Cu 2+ (3d 9 ) electron, which is essentially a 'small polaron' [7], from a lower valent Cu + (3d 10 ) site to a higher valent Cu 2+ (3d 9 ) site. It is reported in literature that the thermally assisted hopping rate of small polaron has marked effect on the electron paramagnetic resonance (EPR) lineshapes [8]; and even at a very low temperature, the thermal hopping rate of small polaron is fast enough to smear out the electron spin-nuclear spin hyperfine interaction to give rise to motionally narrowed EPR lineshapes [9].…”

EPR and magnetic susceptibility studies on polaron dynamics in V2O5-, MoO3- and CuO-containing glasses

“…Glasses containing mixed-valence transition-metal ions [1][2][3] exhibit interesting electron paramagnetic resonance (EPR) lineshapes due to the thermally excited hopping of the small polaron [4] which modulates the lineshapes. As a result, these glasses exhibit semiconducting property [3,5,6] also.…”