High‐Pressure Synthesis and Properties of Solid Solutions Between BiMnO₃ and BiScO₃.

Abstract

3 . -The solid solutions BiMn 1-x Sc x O 3 (0 ≤ x ≤ 1.0) are synthesized from stoichiometric mixtures of Bi2O3 and Mn2O3 (6 GPa, 1383-1443 K, 60-70 min) and characterized by magnetization, specific heat, and DSC measurements. The structure parameters of BiMn0.9Sc0.1O3 are refined by the Rietveld method from powder XRD data. The compound crystallizes in the monoclinic space group C2/c with Z = 8. The solid solutions exhibit long-range ferromagnetic order for x = 0-0.2. For x ≥ 0.4, the samples show spin-glass-like features. -(BELIK*, A. A.; YOKOSAWA, T.; KIMOTO, K.; MATSUI, Y.; TAKAYAMA-MUROMACHI, E.; Chem.

Origin of the Monoclinic-to-Monoclinic Phase Transition and Evidence for the Centrosymmetric Crystal Structure of BiMnO3

“…For example, our studies on the BiMn 1-x Sc x O 3 system showed that H c and M r are noticeably increased with increasing x up to x ) 0.2 (and for x ) 0.05: H c ) 80 Oe and M r ) 0.27µ B ), while the saturated magnetization only slightly decreases. 36 In the case of thin-film samples, there exist additional compressive strains in films. In ref 16, it was suggested that the thin-film samples in reality consist of partially oxidized phases because these samples showed much lower ferromagnetic transition temperatures.…”

No Or Diffuse Phase-Transition With Temperature In One-Dimensional Ising Model?

“…The exact solutions of the heat-capacity and global spontaneous-magnetization of 2D-Ising model 3 given by Onsager 32 and Yang 33 , respectively, do confirm this classification theoretically. However, it is gradually found that there is diffuse phase-transition without the singularities of the thermodynamic potential in the componentheterogeneous [14][15][16][17]26,27 and finite-size 28,29 systems with time.…”

“…Although diffuse phase-transition is common in component-heterogeneous [14][15][16][17]26,27,[45][46][47] and small-size 28,29,48 systems, there is no accurate calculation of the corresponding theoretical models so far 20 . Therefore, the exact results of the all-size order-parameter (Eq.4) in this paper may give some clues to the studies of this kind of phase-transition.…”

“…Traditionally, the description to 1 st and 2 nd -order phase-transitions is based on global order-parameter (such as global spontaneous-magnetization and polarization etc.) 2,3,9,10,30 , but it cannot describe the spatially heterogeneous behavior of the order-parameter corresponding to the diffuse phase-transition in component-heterogeneous [14][15][16][17]26,27,[45][46][47] and small-size 28,29,48 systems. Obviously, for the all-size order-parameter proposed in Ref.…”

“…Our computer simulation of spin orientation states 24,25 also confirm this conclusion intuitively. Moreover, it is concluded that the transition process from high temperature paramagnetic to low temperature ferromagnetic phase is a diffuse phase-transition by comparing with the corresponding phenomena [14][15][16][17][18][19][26][27][28][29] .…”