Cluster-glass behavior of a highly oxygen deficient perovskite, BaBi_0.28Co_0.72O_2.2

Abstract

A highly oxygen deficient perovskite, BaBi(0.28)Co(0.72)O(2.2), was synthesized by solid state reaction. The crystal structure was determined by means of neutron and x-ray powder diffraction. The material exhibits semiconducting behavior with an energy gap of 1.8 eV. The electron diffraction study does not reveal long range Bi:Co ordering; instead it shows the existence of short range ordering in this phase. The AC and DC magnetic susceptibility studies reveal cluster-glass behavior, which has its origin in the interacting ferromagnetic clusters present.

NaCaNi2F7: A frustrated high-temperature pyrochlore antiferromagnet withS=1NKrizan1, Cava2 2015Phys. Rev. B484550View full textAdd to dashboardCite

“…From the AC susceptibility measurements, the expression is useful for characterizing the spin-glass (and can be used for spin-glass-like materials. [27][28][29] A value of 0.024 is obtained for NaCaNi 2 F 7 , which like the Co 2+ fluoride pyrochlores falls into the range expected for an insulating spin glass. 27,28 The value for the current material is slightly lower than 0.029 (NaCaCo 2 F 7 ) and 0.027 (NaSrCo 2 F 7 ).…”

NaCaCo2F7 : A single-crystal high-temperature pyrochlore antiferromagnet

“…A small 0.16 K shift of the peak in the ac susceptibility is seen as a function of frequency, indicative of glassiness in the spin freezing transition. The shift of the peak temperature as a function of frequency can be described by the expression Δ Δ , which is used to characterize spin-glass and spin-glass-like materials [11][12][13]. The value obtained for NaCaCo2F7 is 0.029, which is slightly higher than expected for a canonical spin glass and in the range of what is expected for an insulating spin glass [11,12]; it is an order of magnitude lower than that expected for a super paramagnet and an order of magnitude greater than that of cluster-glasses [11,13].…”

“…; the intrinsic relaxation time (τ0), the activation energy of the process (Ea), and, "the ideal glass temperature" (T0) [11,13] can be extracted. Due to having only five data points and limited temperature resolution (the total observed temperature shift of the peak is only 0.16 K), no physical result could be obtained by fitting all parameters simultaneously, however, good fits could be achieved by fixing τ0 to a physically realistic value.…”

Crystal growth of CsCl-type Yb0.24Sn0.76Ru

“…A similar observation was reported for highly oxygen-deficient disordered perovskite BaBi 1 À x Co x O 2.2 , which forms only in the range of 0.7 oxo0.9. [9]. …”