ATOM INDONESIA
Author's Responses
Article : # 781
Article Title :
SYNTHESIS, STRUCTURAL AND MAGNETIC PROPERTIES
OF La
0.5Ba
0.5CoO
2.75+xLine # Referee’s Comments Author's Responses
This is good experimental work, but there is a problem: the work is a repeat of previous work by different authors. Reference 11 does the same measurement at x=0.05 and the uncited reference by these same authors, I.O.
Troyanchuk et al. JETP Letters 93 (2011) 139, gives results for x=0.12. The authors just publish their experimental results without discussing their context or implications.
Thanks for the comments. From the reference for x = 0.12 or 0.13, at the low temperature it shows phase separation with the coexistence of long range order AFM and FM state. However, in our work the doping increasing a little to x = 0.15, in the neutron diffraction pattern only one phase with long range order AFM was observed at low temperature.
The property of this oxygen content is unique between x = 0 and x = 0.25. We focus on the analysis of magnetic structure and determine the structure by Rietveld refinement method and the representation theory.
We take the Reviewer’s suggestion and have added discussion of experimental results from references in the second paragraph. In this paper we cited the reference for the sample x = 0.12 from another paper of the same authors (V.
Sikolenko, V. Efimov, I.O. Troyanchuk, D.V. Karpinsky, M.V. Bushinsky and D.
Sheptyakov, J. Phys. Conf. Ser.,391, (2012) 012106.). We follow the reviewer’s suggestion to add the reference, I. O. Troyanchuk, et al., JETP Lett., 93, (2011) 139.
I believe that it is impossible for a microscopically homogeneous material to show both long range antiferromagnetic order
and short range ferromagnetic clusters. This can only come about if there are microscopic
inhomogeneities in the crystal. Thus the defects must not be random, but must show
some clustering. Further the antiferromagnetic Bragg peaks at x=0.06
(figure 2(a)) show a much more gradual
Thanks for the comments. From the view point of phase diagram, at x = -0.15 the sample shows the long range antiferromagnetic order, however as the doping increase to x = 0.15 or 0.25, it exhibits long range FM order. Near the phase boundary of AFM and FM, it is natural to see the coexistence of AFM and FM state, which comes from the electronic origin. Because in vicinity of
transition than is usual, suggesting either a magnetic critical index beta of about 0.5 or (more likely) regions with Neel temperature
varying from 210K to about half that temperature. Reference 11 shows a more normal temperature dependence, supporting
the latter possibility.
the boundary, the energy of AFM and FM state is very close. As reported in the Colossal magnetoresistance (CMR) materials (reference: Y. Tokura, Rep.
Prog. Phys. 69 (2006) 797–851), they also show the coexistence of AFM and FM state near the boundary of phase diagram. So we think that the coexistence of long range antiferromagnetic order and short range
ferromagnetic clusters in
La0.5Ba0.5CoO2.75+x does not necessarily arise from the chemical inhomogeneity.
As for the integrated intensity of antiferromagnetic Bragg peaks at x =0.06 shows gradual transition than is usual, it may either come from the existence of short range FM order, which results in not pure second order phase transition, or come from the chemical inhomogeneity, which causes a broad window of Neel temperature.
The uncited work by Troyanchuk et al. for x=0.12 shows a gradual phase separation below 200K, which is not surprising when coexistent ferromagnetism and
antiferromagnetic regions are reported.
Surprisingly the powder pattern in figure 3(b) shows no sign of this. Probably this is due to different annealing times or cooling rates.It is interesting that reference 9 and 17 both show that at x=0.25 there is long range
antiferromagnetic order coexistent which short range ferromagnetic clusters. Why are the results at x=0.06 and at x=0.25 similar while the results at in-between values of x (x=0.12 and 0.15) are different?
Thanks for the comments. For x = 0.06, it shows long range antiferromagnetic order coexists with short range
ferromagnetic clusters. From the reference 9 and 17, It has been reported that long range order FM state and small clusters of short range order AFM coexist in ground state in
La0.5Ba0.5CoO2.75+x (x = 0.25). As the x value increase, the AFM order is suppressed while FM order grows.
Therefore, it is possible that the coexistence of long range order AFM and long range order FM at x = 0.12 evolves into the coexistence of long range order FM and short range order AFM at x = 0.15.
Please return to Atom Indonesia Editorial Office via supplementary file in OJS aplication.
Date Summary of changes
1. Add the discussion of experimental results from references in the 2nd paragraph.
2. Modify the sample doping value of x = 0.15 to x = 0.16 and x = 0.06 to x = 0.08 based on our recent experimental result of Iodometric titration.
3. Add the discussion of coexistence of AFM and FM state in the 5th paragraph.
4. Modify the tables according to the requirement of the journal.
5. Add the reference, I. O. Troyanchuk, et al., JETP Lett., 93, (2011) 139.
