Doping effects on the phase separation in perovskiteLa0.67−xBixCa<

Abstract

Effects of Bi, Cr, and Fe doping on phase separation of La 0.67 Ca 0.33 MnO 3 have been experimentally studied. As proved by the electron-spin resonance and neutron-diffraction studies, partial replacement of La by Bi causes the simultaneous occurrence of ferromagnetic ͑FM͒ phase and charge-ordered antiferromagnetic phase. As a consequence, two subsequent magnetic transitions at ϳ120 K and ϳ230 K are resulted. A strong coupling between the coexisted phases is assumed, which is responsible for the insensitivity of T c (L), the higher Curie temperature, to Bi doping after the appearance of phase separation, and consistent with the discontinuous variation of T c (L) with Cr doping. As expected, the substitution of Cr for Mn in this case promotes the FM order, but its effects are significantly different for the two magnetic states. Each Cr drives ϳ100 neighboring unit cells, for the high-moment state, and ϳ60 unit cells, for the low-moment state, into the FM state. Two definite processes can be identified for the melting of the charge-ordered phase. The FM fraction increases rapidly in the initial stage of Cr doping, and then slowly when the FM population exceeds ϳ90%. This could be a common feature of the phase-separated system suffering from random-phase fluctuation according to a theoretical analysis. Exactly opposite effects on phase constituent are produced by Cr doping and Bi doping, and 1% Cr are equivalent to ϳ4.6% Bi. In contrast, both Cr doping and magnetic field promote the FM order. 1% Cr correspond to a field of ϳ4.5 T for the low-moment state and 6 T for the high-moment state, reducing the energy difference between the charge ordering and the FM states by ϳ0.96 meV/Mn and ϳ1.3 meV/Mn, respectively.

Effect of progressive substitution of La3+ by Bi3+ on the structure, magnetic and transport properties of La0.67Sr0.33Mno3

“…Following this trend of work, more specific studies were focused on one of the main contributions to the physical properties of manganites. This is change in the crystallographic structure while maintaining a fixed doping level [6]. Several authors completed a great number of different cationic substitutions, which are briefly summarized in the phase diagram proposed by Hwang et al [7].…”

Disorder-driven phase transition in La0.37D0.30Ca0.33MnO3 (D = Bi, Sm) manganites

“…The electron spin resonance (ESR), magnetization and neutron diffraction studies on La 0.67−x Bi x Ca 0.33 MnO 3 (x ≤ 0.20) reveal that the partial replacement of La by Bi develops the charge ordered AFM phase. 15 A large magnetic entropy change 20 and 087105-2 R. Ade and R. Singh AIP Advances 5, 087105 (2015) state switching behavior 21 have been also reported in Bi doped La-manganites. The evolution different properties with Bi doping can be due to the effect of 6 s loan pair of Bi 3+ ions.…”

“…The decrease in the unit-cell volume for these samples compared to La 0.67 Ca 0. 33 13,15,18 From the refinement the estimated atomic positions for the samples are listed in Table I. Microstructure of the samples Fig.…”

“…9 The disorder induced second-order FM-PM phase transition is reported in the literature. [12][13][14] There are reports on the effect of Bi 11,[15][16][17][18][19][20][21] and Sm 13,[22][23][24] doping at La-site in La-manganites. M. C. Walsh et al 11 have investigated magnetic and electronic properties of La 0.67−x Bi x Ca 0.33 MnO 3 (x ≤ 0.16).…”

Magnetic and Charge-Ordering Properties of Bi0.2−x Pr x Ca0.8MnO3 (0.0=x=0.20) Perovskite Manganite

“…Zhang et al and it has been found that T CO and antiferromagnetic (AFM) ordering temperature T N occurring below T CO decrease with increasing Gd-doping level [14]. Despite several investigations relating to the doping on A site in Bi 1−x Ca x MnO 3 [15][16][17][18][19], the physical feature of CO, the interplay between the different magnetic phases and the nature of the resulting meta-magnetic phase is still unclear. Further, the nature of the phase separation (PS) [20] that plays a crucial role in determining the magnetic landscape of manganites is also only vaguely understood.…”