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Structural and magnetic anisotropy in YBa2Cu3O7/La0.67Sr0.33MnO3 bilayer on SrTiO3 substrate

by Ankita Singh, Ram Prakash Pandeya, Sawani Dutta, Srinivas C. Kandukuri and Kalobaran Maiti

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Submission summary

Authors (as registered SciPost users): Ankita Singh
Submission information
Preprint Link: scipost_202207_00021v2  (pdf)
Date accepted: 2023-04-25
Date submitted: 2022-12-22 14:42
Submitted by: Singh, Ankita
Submitted to: SciPost Physics Proceedings
Proceedings issue: International Conference on Strongly Correlated Electron Systems (SCES2022)
Ontological classification
Academic field: Physics
Specialties:
  • Condensed Matter Physics - Experiment
Approach: Experimental

Abstract

We study the magnetic properties and emergence of superconductivity in YBa2Cu3O7 (YBCO)/ La0.67Sr0.33MnO3 (LSMO) heterostructures. Bilayer films of superconducting layer, YBCO, and ferromagnetic layer, LSMO were grown on SrTiO3 (STO) (001) substrate using ultrahigh vacuum Pulsed Laser Deposition system. Magnetization data at 100 K as a function of applied magnetic field shows ferromagnetic behaviour due to the LSMO layer. Cooling below 100 K leads to superconductivity in this material; the onset of superconductivity occurs at a temperature, Tc(Onset) of 86 K for Hext\perp c (in-plane) & 84 K for Hext||c (out-of-plane) under 100 Oe applied field. In-plane magnetic measurements show significant suppression of diamagnetic behaviour as compared to the out-of-plane measurements. The susceptibility signals are higher for out-of-plane direction. Such strong anisotropy in magnetism and the transition temperatures reveal complex interplay of magnetism and superconductivity in this system and calls for further study in this direction.

Author comments upon resubmission

We thank both referees for their time in critically evaluating the manuscript, comments, and recommendations. We have revised the manuscript considering all the comments. Response to the comments is given below.
1. Major criticism is the magnetic anisotropy interpretation. It is based on change of the Tc value from H perpendicular to in-plane with c-axis. This is estimated from magnetization studies. But the variation is within 2K (86K to 84K) and in most cases the error bar (deltaT) on exact estimation of Tc value from ZFC curves is comparable to the 2K range. So an inset of first-order derivative showing exact location of peak at Tc would be more convincing and add value to the manuscript.

Reply: We have added the first-order derivative of the susceptibility curve as an inset in Fig.2, which clearly show the change in the Tc, SC with the change in the direction of the applied magnetic field.

2. A discussion on the effect of superconductivity on the magnetism is not addressed adequately. Few possible publications from Prof. C. Bernhard (pioneers in this field) discussing interplay of superconductivity and magnetism in these heterostructure can be used for discussions: Nature Materials 8, pages 315–319 (2009), Physical Review B 87, 115105 (2013), Physical Review B 100, 115129 (2019)

Reply: We agree with the referee and added a paragraph on page no. 4 in the revised manuscript discussing the change in superconductivity/ferromagnetism in bilayer thin films due to the proximity effect. We have also added the suggested references.

List of changes

1. Page 3, Fig. 2: Added an inset showing the derivative of susceptibility for different magnetization directions. The following text is added to describe the inset.

“Such dependence of the onset temperature for superconductivity, Tc on the direction of externally applied magnetic field is confirmed from the first derivative of the susceptibility (see inset of Fig. 2).”

2. Page 4: Added the following paragraph

“The dependence of the onset temperature, Tc, SC and the magnetic behavior on the magnetization direction suggests possible coupling of the superconducting layer of YBCO through the ferromagnetic layer of LSMO. Similar observation in bilayer thin films of La0.66Ca0.33MnO3 (LCMO)/YBCO in earlier studies [16,17] is consistent with these results. It appears that the ferromagnetic ordering in the LSMO layer induces magnetic ordering of the Cu moments in the YBCO film leading to significant renormalization of the magnetism of the LSMO film. The formation of non-collinear magnetic ordering at the interface can persuade spin-triplet component of the superconductivity ordering that has a long-ranged proximity effect in the ferromagnetic layers [18,19].”

3. Page 4: Added new references [16], [17], [18], and [19].

Published as SciPost Phys. Proc. 11, 007 (2023)

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