Giant dielectric constant, magnetocaloric effect and spin-phonon coupling in EuTbCoMnO6 semiconductor

Alam, Mohd; Ghosh, Labanya; Dixit, Srishti; Jena, Madhusmita; Kumari, Shweta; Kumar, Satya Vijay; Kumar, Dheeraj; Verma, Abhineet; Ghosh, Anup K.; Saha, Satyen; Choudhary, R. J.; Chatterjee, Sandip

doi:10.1016/j.physb.2023.415043

Cited by 3 publications

(2 citation statements)

References 102 publications

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“…The analysis of Co 2 p in both samples ( Figure 4 c,d) revealed the presence of two components, one at 780.2 ± 0.1 eV, which can be attributed to Co 3+ , whereas the other component at 798.2 ± 0.2 eV can be ascribed to Co 2+ 65 . There is an additional component needed for the correct fitting of the spectra at 783.6 eV, which corresponds to the Auger Fe LMM .…”

Section: Resultsmentioning

confidence: 93%

Magnetoelastic Coupling Evidence by Anisotropic Crossed Thermal Expansion in Magnetocaloric RSrCoFeO₆ (R = Sm, Eu) Double Perovskites

Silva,

Rodrigues,

Gainza

et al. 2024

Inorg. Chem.

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Double perovskite oxides, characterized by their tunable magnetic properties and robust interconnection between the lattice and magnetic degrees of freedom, present an enticing foundation for advanced magnetic refrigeration materials. Herein, we delve into the influence of rare-earth elements on RSrCoFeO 6 (R = Sm, Eu) disordered double perovskites by examining their structural, electronic, magnetic, and magnetocaloric properties. Temperature-dependent synchrotron X-ray diffraction analysis confirmed the stability of the orthorhombic phase (Pnma) across a wide temperature range. X-ray photoemission spectroscopy revealed that both Sm and Eu are in the 3+ state, whereas multiple states for Co 2+/3+ and Fe 3+/4+ are identified. The magnetic investigation and magnetocaloric effect (MCE) analysis brought to light the presence of a long-range antiferromagnetic (AFM) order with a second-order phase transition (SOPT) in both samples. The maximum magnetic entropy change ΔS M max was approximately 0.9 J/kg K for both samples at applied field 0−7 T, manifesting prominently above Neel temperatures T N ≈ 93 K (Sm) and 84 K (Eu). Nevertheless, different relative cooling powers (RCP) of 112.6 J/kg (Sm) and 95.5 J/kg (Eu) were observed. A detailed analysis of the temperature-dependent lattice parameters shed light on a distinct magnetocaloric effect across the magnetic transition temperature, unveiling an anisotropic thermal expansion [α V = 1.41 × 10 −5 K −1 (Sm) and α V = 1.54 × 10 −5 K −1 (Eu)] wherein the thermal expansion axial ratio α b Sm /α b Eu = 0.61 became lower with increasing temperature, which suggests that the Eu sample experiences a greater thermal expansion in the b-axis direction. At the atomic bonding level, the evidence for magnetoelastic coupling around the magnetic transition temperatures T N was found through the anomalies along the average Co/Fe−O bond distance, formal valence, octahedral distortion, as well as an anisotropic lattice expansion.

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Section: Resultsmentioning

confidence: 93%

Magnetoelastic Coupling Evidence by Anisotropic Crossed Thermal Expansion in Magnetocaloric RSrCoFeO₆ (R = Sm, Eu) Double Perovskites

Silva,

Rodrigues,

Gainza

et al. 2024

Inorg. Chem.

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“…Double perovskite (DP) alloys, represented as A 2 BB'O 6 (A represents alkaline or rare earth ions, B and B' stand for transition metal ions) have attracted great attention due to their compelling properties like substantial magnetodielectric coupling, colossal magnetoresistance, giant dielectric constant, magnetocaloric effects, spindriven ferroelectricity, giant exchange bias, and spin-phonon coupling [1][2][3][4]. The physical properties of DP materials are highly sentitive to the cation ordering degree over octahedral sites, influenced by the differences in charge and ionic size between the B and B′ elements.…”

Section: Introductionmentioning

confidence: 99%

Anomalous magnetic and electrical properties of disordered double perovskite alloy LaCaMnFeO₆

Tran,

Hoang,

Khan

et al. 2024

Mater. Res. Express

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Double perovskite alloys are of significant interest owing to their intriguing magnetic properties and potential practical applications. In this study, we provided a detailed report on the structural, electrical and magnetic features of the double perovskite LaCaMnFeO6, prepared via the conventional solid-state reaction technique. Neutron diffraction analysis showed that the sample is single-phase adopting the Pnma orthorhombic structure with random distribution of La3+/Ca2+ and Mn4+/Fe3+ ions on A- and B-sites, respectively. A long-range G-type antiferromagnetic order was formed below TN = 250 K. Magnetic measurements unveiled a cluster glassy behavior at low temperatures with a complex distribution of cluster magnetic anisotropy energy. Ferromagnetic clusters consisting of two Mn4+ and one Fe3+ were found to exist in the paramagnetic phase. The complex magnetic properties of LaCaMnFeO6 are attributed to the cation disorder effect combined with the competition between magnetic interactions. Unusual electrical behavior with a large positive magnetoresistive effect was observed and correlated to magnetic phase transitions.

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Maxwell–Wagner Polarization and Mixed Ferromagnetic and Antiferromagnetic State in Eu₂CoMnO₆

Alam,

Kumar,

Kumar

et al. 2023

Physica Status Solidi (b)

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Herein, the electrical and magnetic properties of polycrystalline Eu2CoMnO6 are explored. More specifically, based on transport, dielectric, and impedance measurements, a thermally activated dielectric polarization near room temperature is reported. The valence states of transition metals in the Eu2CoMnO6 sample are studied by measuring the X‐ray absorption spectra at both Co‐L2,3 and Mn‐L2,3 edges. Moreover, based on magnetization, X‐ray absorption spectroscopy, and X‐ray magnetic circular dichroism measurements, the coexistence of competing ferromagnetic and antiferromagnetic phases is probed. Dielectric measurement shows a large dielectric constant near room temperature along with a large frequency dispersion. The temperature‐dependent resistivity, Cole–Cole plot, and imaginary part of impedance confirm the semiconducting nature of Eu2CoMnO6. Temperature‐dependent magnetization shows a second‐order magnetic transition below 125 K. Isothermal magnetization versus magnetic field loop shows first‐order metamagnetic transition, driven by mixed magnetic state owing to the presence of antisite disorder and antiphase boundary.

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Giant dielectric constant, magnetocaloric effect and spin-phonon coupling in EuTbCoMnO6 semiconductor

Cited by 3 publications

References 102 publications

Magnetoelastic Coupling Evidence by Anisotropic Crossed Thermal Expansion in Magnetocaloric RSrCoFeO₆ (R = Sm, Eu) Double Perovskites

Magnetoelastic Coupling Evidence by Anisotropic Crossed Thermal Expansion in Magnetocaloric RSrCoFeO₆ (R = Sm, Eu) Double Perovskites

Anomalous magnetic and electrical properties of disordered double perovskite alloy LaCaMnFeO₆

Maxwell–Wagner Polarization and Mixed Ferromagnetic and Antiferromagnetic State in Eu₂CoMnO₆

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Giant dielectric constant, magnetocaloric effect and spin-phonon coupling in EuTbCoMnO6 semiconductor

Cited by 3 publications

References 102 publications

Magnetoelastic Coupling Evidence by Anisotropic Crossed Thermal Expansion in Magnetocaloric RSrCoFeO6 (R = Sm, Eu) Double Perovskites

Magnetoelastic Coupling Evidence by Anisotropic Crossed Thermal Expansion in Magnetocaloric RSrCoFeO6 (R = Sm, Eu) Double Perovskites

Anomalous magnetic and electrical properties of disordered double perovskite alloy LaCaMnFeO6

Maxwell–Wagner Polarization and Mixed Ferromagnetic and Antiferromagnetic State in Eu2CoMnO6

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Magnetoelastic Coupling Evidence by Anisotropic Crossed Thermal Expansion in Magnetocaloric RSrCoFeO₆ (R = Sm, Eu) Double Perovskites

Magnetoelastic Coupling Evidence by Anisotropic Crossed Thermal Expansion in Magnetocaloric RSrCoFeO₆ (R = Sm, Eu) Double Perovskites

Anomalous magnetic and electrical properties of disordered double perovskite alloy LaCaMnFeO₆

Maxwell–Wagner Polarization and Mixed Ferromagnetic and Antiferromagnetic State in Eu₂CoMnO₆