Shifting Valencies and Magnetic Responses in La-Based High-Entropy Oxide Perovskite Thin Films with Variable Mn Presence

Duncan Miertschin; Alessandro R. Mazza; Balaram Regmi; Sundar Kunwar; Poshan Kandel; Mohana V. Kante; Ryan Mueller; Clayton Hearn; Peter Bencok; David A. Jack; Thomas Prokscha; Andreas Suter; Zaher Salman; Alan Farhan; Thomas Zac Ward

doi:10.1021/acsaelm.6c00186

Shifting Valencies and Magnetic Responses in La-Based High-Entropy Oxide Perovskite Thin Films with Variable Mn Presence

Duncan Miertschin
, Alessandro R. Mazza
, Balaram Regmi
, Sundar Kunwar
, Poshan Kandel
, Mohana V. Kante
, Ryan Mueller
, Clayton Hearn
, Peter Bencok
, David A. Jack
, Thomas Prokscha
, Andreas Suter
, Zaher Salman
, Alan Farhan
, Thomas Zac Ward

Research output: Contribution to journal › Article › peer-review

Abstract

Chemical disorder in compositionally complex perovskite oxides generates a broad distribution of exchange pathways and spin states, but the microscopic origin and spatial homogeneity of the resulting magnetic phases remain debated. Here, we tune the Mn fraction (x = 0.2–0.6) in epitaxial La(Cr, Mn, Fe, Co, Ni)O₃ thin films and resolve the coupled evolution of valence, spin state, and magnetism using element-specific x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD). Mn enrichment drives an internal redistribution of charge, in which Mn evolves toward a Mn³⁺-rich mixed valence, while Co converts from predominantly Co³⁺ to high-spin Co²⁺. This valence/spin-state coupling amplifies the Mn- and Co-derived ferromagnetic response by nearly an order of magnitude while increasing the magnetic onset temperature to at least 250 K, whereas Fe and Cr remain essentially trivalent with weak dichroism. Depth-resolved low-energy muon spin spectroscopy (LE-μSR) shows magnetic homogeneity through the film thickness, with a secondary relaxation maximum near 25 K indicating a low-temperature dynamical crossover consistent with frustrated magnetism in a strongly disordered spin lattice.

Original language	English
Pages (from-to)	4523-4530
Number of pages	8
Journal	ACS Applied Electronic Materials
Volume	8
Issue number	11
DOIs	https://doi.org/10.1021/acsaelm.6c00186
State	Published - Jun 9 2026

Funding

This project is supported by the Robert A. Welch Foundation (Grant No. AA-2276-20260402). Synthesis was supported by the U.S. DOE, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division at Oak Ridge National Laboratory. Structural characterization was conducted at the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. The XAS/XMCD experiments were carried out at beamline I10 of the Diamond Light Source. The authors are grateful for the use of the Rigaku SmartLab XRD provided by Baylor’s Materials Testing and Characterization Core. This work is partly based on experiments performed at the Swiss Muon Source SμS, Paul Scherrer Institute, Villigen, Switzerland.

Keywords

XAS
XMCD
high-entropy oxides
magnetism
muon spectroscopy

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10.1021/acsaelm.6c00186

Cite this

Miertschin, D., Mazza, A. R., Regmi, B., Kunwar, S., Kandel, P., Kante, M. V., Mueller, R., Hearn, C., Bencok, P., Jack, D. A., Prokscha, T., Suter, A., Salman, Z., Farhan, A., & Ward, T. Z. (2026). Shifting Valencies and Magnetic Responses in La-Based High-Entropy Oxide Perovskite Thin Films with Variable Mn Presence. ACS Applied Electronic Materials, 8(11), 4523-4530. https://doi.org/10.1021/acsaelm.6c00186

@article{bb57df295cb24347a574e765d0ad96c1,

title = "Shifting Valencies and Magnetic Responses in La-Based High-Entropy Oxide Perovskite Thin Films with Variable Mn Presence",

abstract = "Chemical disorder in compositionally complex perovskite oxides generates a broad distribution of exchange pathways and spin states, but the microscopic origin and spatial homogeneity of the resulting magnetic phases remain debated. Here, we tune the Mn fraction (x = 0.2–0.6) in epitaxial La(Cr, Mn, Fe, Co, Ni)O3 thin films and resolve the coupled evolution of valence, spin state, and magnetism using element-specific x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD). Mn enrichment drives an internal redistribution of charge, in which Mn evolves toward a Mn3+-rich mixed valence, while Co converts from predominantly Co3+ to high-spin Co2+. This valence/spin-state coupling amplifies the Mn- and Co-derived ferromagnetic response by nearly an order of magnitude while increasing the magnetic onset temperature to at least 250 K, whereas Fe and Cr remain essentially trivalent with weak dichroism. Depth-resolved low-energy muon spin spectroscopy (LE-μSR) shows magnetic homogeneity through the film thickness, with a secondary relaxation maximum near 25 K indicating a low-temperature dynamical crossover consistent with frustrated magnetism in a strongly disordered spin lattice.",

keywords = "XAS, XMCD, high-entropy oxides, magnetism, muon spectroscopy",

author = "Duncan Miertschin and Mazza, \{Alessandro R.\} and Balaram Regmi and Sundar Kunwar and Poshan Kandel and Kante, \{Mohana V.\} and Ryan Mueller and Clayton Hearn and Peter Bencok and Jack, \{David A.\} and Thomas Prokscha and Andreas Suter and Zaher Salman and Alan Farhan and Ward, \{Thomas Zac\}",

note = "Publisher Copyright: {\textcopyright} 2026 The Authors. Published by American Chemical Society.",

year = "2026",

month = jun,

day = "9",

doi = "10.1021/acsaelm.6c00186",

language = "English",

volume = "8",

pages = "4523--4530",

journal = "ACS Applied Electronic Materials",

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Miertschin, D, Mazza, AR, Regmi, B, Kunwar, S, Kandel, P, Kante, MV, Mueller, R, Hearn, C, Bencok, P, Jack, DA, Prokscha, T, Suter, A, Salman, Z, Farhan, A & Ward, TZ 2026, 'Shifting Valencies and Magnetic Responses in La-Based High-Entropy Oxide Perovskite Thin Films with Variable Mn Presence', ACS Applied Electronic Materials, vol. 8, no. 11, pp. 4523-4530. https://doi.org/10.1021/acsaelm.6c00186

TY - JOUR

T1 - Shifting Valencies and Magnetic Responses in La-Based High-Entropy Oxide Perovskite Thin Films with Variable Mn Presence

AU - Miertschin, Duncan

AU - Mazza, Alessandro R.

AU - Regmi, Balaram

AU - Kunwar, Sundar

AU - Kandel, Poshan

AU - Kante, Mohana V.

AU - Mueller, Ryan

AU - Hearn, Clayton

AU - Bencok, Peter

AU - Jack, David A.

AU - Prokscha, Thomas

AU - Suter, Andreas

AU - Salman, Zaher

AU - Farhan, Alan

AU - Ward, Thomas Zac

PY - 2026/6/9

Y1 - 2026/6/9

N2 - Chemical disorder in compositionally complex perovskite oxides generates a broad distribution of exchange pathways and spin states, but the microscopic origin and spatial homogeneity of the resulting magnetic phases remain debated. Here, we tune the Mn fraction (x = 0.2–0.6) in epitaxial La(Cr, Mn, Fe, Co, Ni)O3 thin films and resolve the coupled evolution of valence, spin state, and magnetism using element-specific x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD). Mn enrichment drives an internal redistribution of charge, in which Mn evolves toward a Mn3+-rich mixed valence, while Co converts from predominantly Co3+ to high-spin Co2+. This valence/spin-state coupling amplifies the Mn- and Co-derived ferromagnetic response by nearly an order of magnitude while increasing the magnetic onset temperature to at least 250 K, whereas Fe and Cr remain essentially trivalent with weak dichroism. Depth-resolved low-energy muon spin spectroscopy (LE-μSR) shows magnetic homogeneity through the film thickness, with a secondary relaxation maximum near 25 K indicating a low-temperature dynamical crossover consistent with frustrated magnetism in a strongly disordered spin lattice.

AB - Chemical disorder in compositionally complex perovskite oxides generates a broad distribution of exchange pathways and spin states, but the microscopic origin and spatial homogeneity of the resulting magnetic phases remain debated. Here, we tune the Mn fraction (x = 0.2–0.6) in epitaxial La(Cr, Mn, Fe, Co, Ni)O3 thin films and resolve the coupled evolution of valence, spin state, and magnetism using element-specific x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD). Mn enrichment drives an internal redistribution of charge, in which Mn evolves toward a Mn3+-rich mixed valence, while Co converts from predominantly Co3+ to high-spin Co2+. This valence/spin-state coupling amplifies the Mn- and Co-derived ferromagnetic response by nearly an order of magnitude while increasing the magnetic onset temperature to at least 250 K, whereas Fe and Cr remain essentially trivalent with weak dichroism. Depth-resolved low-energy muon spin spectroscopy (LE-μSR) shows magnetic homogeneity through the film thickness, with a secondary relaxation maximum near 25 K indicating a low-temperature dynamical crossover consistent with frustrated magnetism in a strongly disordered spin lattice.

KW - XAS

KW - XMCD

KW - high-entropy oxides

KW - magnetism

KW - muon spectroscopy

UR - https://www.scopus.com/pages/publications/105041271127

U2 - 10.1021/acsaelm.6c00186

DO - 10.1021/acsaelm.6c00186

M3 - Article

AN - SCOPUS:105041271127

SN - 2637-6113

VL - 8

SP - 4523

EP - 4530

JO - ACS Applied Electronic Materials

JF - ACS Applied Electronic Materials

IS - 11

ER -

Shifting Valencies and Magnetic Responses in La-Based High-Entropy Oxide Perovskite Thin Films with Variable Mn Presence

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