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Alam M, Chatterjee S. B-site order/disorder in A 2BB'O 6and its correlation with their magnetic property. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:223001. [PMID: 36888997 DOI: 10.1088/1361-648x/acc295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
The disorder in any system affects their physical behavior. In this scenario, we report the possibility of disorder in A2BB'O6oxides and their effect on different magnetic properties. These systems show anti-site disorder by interchanging B and B' elements from their ordered position and giving rise to an anti-phase boundary. The presence of disorder leads to a reduction in saturationMand magnetic transition temperature. The disorder prevents the system from sharp magnetic transition which originates short-range clustered phase (or Griffiths phase) in the paramagnetic region just above the long-range magnetic transition temperature. Further, we report that the presence of anti-site disorder and anti-phase boundary in A2BB'O6oxides give different interesting magnetic phases like metamagnetic transition, spin-glass, exchange bias, magnetocaloric effect, magnetodielectric, magnetoresistance, spin-phonon coupling, etc.
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Affiliation(s)
- Mohd Alam
- Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Sandip Chatterjee
- Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
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2
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Khan A, Rajput S, Anas M, Malik VK, Maitra T, Nath TK, Taraphder A. The effect of antisite disorder on magnetic and exchange bias properties of Gd-substituted Y 2CoMnO 6double perovskite. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:435801. [PMID: 35973421 DOI: 10.1088/1361-648x/ac8a35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Combining experimental investigations and first-principles density functional theory (DFT) calculations, we report physical and magnetic properties of Gd-substituted Y2CoMnO6double perovskite, which are strongly influenced by antisite-disorder-driven spin configurations. On Gd doping, Co and Mn ions are present in mixed-valence (Co3+, Co2+, Mn3+and Mn4+) states. Multiple magnetic transitions have been observed: (i) paramagnetic to ferromagnetic transition is found to occur atTC= 95.5 K, (ii) antiferromagnetic transition atTN= 47 K is driven by3d-4fpolarization and antisite disorder present in the sample, (iii) change in magnetization belowT⩽20 K, primarily originating from Gd ordering, as revealed from our DFT calculations. AC susceptibility measurement confirms the absence of any spin-glass or cluster-glass phases in this material. A significantly large exchange bias effect (HEB= 1.07 kOe) is found to occur below 47 K due to interfaces of FM and AFM clusters created by antisite-disorder.
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Affiliation(s)
- Anasua Khan
- Department of Physics, Indian Institute of Technology, Kharagpur 721302, India
| | - Sarita Rajput
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - M Anas
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - V K Malik
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - T Maitra
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - T K Nath
- Department of Physics, Indian Institute of Technology, Kharagpur 721302, India
| | - A Taraphder
- Department of Physics, Indian Institute of Technology, Kharagpur 721302, India
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3
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Investigation of Magnetic Entropy Change in Intermetallic Compounds SmNi3−xFex Based on Maxwell Relation and Phenomenological Model. CRYSTALS 2022. [DOI: 10.3390/cryst12040481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this study, we investigate the crystal structure, magnetic, and magnetocaloric effect properties in the intermetallic compounds SmNi3−xFex using a phenomenological model based on Landau mean-field theory and Maxwell relation (conventional method). SmNi3−xFex compounds were prepared under high pure argon by arc melting. To minimize the amount of other possible impurity phases, the ingots were heat-treated at 1073 K for seven days. X-ray diffraction (XRD) under and without an applied magnetic field was used for the structural study. Rietveld analysis with FullProf computer code was used to analyze X-ray diffraction data. The magnetization against temperature was measured under several applied magnetic fields. After the partial substitutions of nickel atom with iron one, we notice an increase of cell parameters. In addition, Curie temperature value increases significantly with the increase of iron content. According to the Landau model, SmNi3−xFex compounds exhibit a second-order magnetic phase transition. The magnetic entropy change was determined with theoretical and experimental methods. Finally, a comparison between theoretical magnetic entropy change and the experimental show an agreement between the two methods.
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Mazumdar D, Rawat R, Banik S, Das K, Das I. Real-space imaging of magnetic phase transformation in single crystalline Sm-Ca-Sr based manganite compound. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:235402. [PMID: 33836523 DOI: 10.1088/1361-648x/abf6a7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
Low-temperature-high-magnetic field magnetic force microscopy studies on colossal magnetoresistance material Sm0.5Ca0.25Sr0.25MnO3have been carried out. These measurements provide real-space visualization of antiferromagnetic-ferromagnetic (AFM-FM) transition on sub-micron length scale and explain the presence of AFM-FM transition in the temperature-dependent magnetization measurements, but the absence of corresponding metal-insulator transition in temperature-dependent resistivity measurements at the low magnetic field. Distribution of transition temperature over the scanned area indicates towards the quench disorder broadening of the first-order magnetic phase transition. It shows that the length scale of chemical inhomogeneity extends over several micrometers.
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Affiliation(s)
- Dipak Mazumdar
- Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata 700 064, India
| | - Rajeev Rawat
- UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 425001, India
| | - Sanjib Banik
- Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata 700 064, India
- Experimentelle Physik 3 (EP III), University of Wuerzburg, 97074 Wurzburg, Germany
| | - Kalipada Das
- Seth Anandram Jaipuria College, 10 Raja Naba Krishna Street, Kolkata 700005, India
| | - I Das
- Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata 700 064, India
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5
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Solanki S, Dhruv D, Boricha H, Zankat A, Rathod K, Rajyaguru B, Trivedi R, Joshi A, Mukherjee S, Solanki P, Shah N. Charge transport mechanisms and magnetoresistance behavior of La0.6Pr0.1Ca0.3MnO3 manganite. J SOLID STATE CHEM 2020. [DOI: 10.1016/j.jssc.2020.121446] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Alam M, Singh P, Anand K, Pal A, Ghosh S, Ghosh AK, Singh RK, Joshi AG, Chatterjee S. Extraordinary magnetic properties of double perovskite Eu 2CoMnO 6wide band gap semiconductor. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:365802. [PMID: 32541098 DOI: 10.1088/1361-648x/ab8ecc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
Some novel magnetic behaviours in double perovskite Eu2CoMnO6(ECMO) have been reported. The x-ray photoemission spectroscopy study shows the presence of mixed valence states of transition metal ions. The UV-visible absorption spectroscopic study suggests that the ECMO has a direct wide band gap. A second-order magnetic phase transition as a sudden jump in the magnetization curve has been observed around 124.5 K. The large bifurcation between the zero field cooling and field cooling, suggests existence of strong spin frustration in the system. The inverse DC susceptibility confirms the presence of the Griffiths like phase. Sharp steps in magnetization have been observed in theM-Hcurve at 2 K, which vanishes on increasing temperature. The AC susceptibility study demonstrates the Hopkinson like effect as well as the presence of volume spin-glass-like behaviour. The temperature dependent Raman spectrum shows the presence of spin-phonon coupling.
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Affiliation(s)
- Mohd Alam
- Department of Physics, Indian Institute of Technology (B.H.U.), Varanasi-221005, India
| | - Prajyoti Singh
- Department of Physics, Indian Institute of Technology (B.H.U.), Varanasi-221005, India
| | - Khyati Anand
- Department of Physics, Indian Institute of Technology (B.H.U.), Varanasi-221005, India
| | - Arkadeb Pal
- Department of Physics, Indian Institute of Technology (B.H.U.), Varanasi-221005, India
| | - Surajit Ghosh
- Department of Physics, Indian Institute of Technology (B.H.U.), Varanasi-221005, India
| | - A K Ghosh
- Department of Physics, Banaras Hindu University, Varanasi-221005, India
| | - Ranjan K Singh
- Department of Physics, Banaras Hindu University, Varanasi-221005, India
| | - Amish G Joshi
- CSIR - Central Glass & Ceramic Research Institute, Rajkot-382330, India
| | - Sandip Chatterjee
- Department of Physics, Indian Institute of Technology (B.H.U.), Varanasi-221005, India
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7
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Mao Q, Chen B, Yang J, Zhang Y, Wang H, Fang M. Critical properties of the quasi-two-dimensional metallic ferromagnet Fe 2.85GeTe 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:345802. [PMID: 30020086 DOI: 10.1088/1361-648x/aad43b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We have investigated the critical behavior of Fe2.85GeTe2 single crystals near the paramagnetic-ferromagnetic transition by bulk dc magnetization measurements. The critical exponents β, γ and δ, obtained from modified Arrott plot, Kouvel-Fisher method, and critical isothermal magnetization analysis, could fulfill the Widom scaling law. The self-consistency and reliability of these exponents are further verified by the magnetic state equations below and above the Curie temperature at high magnetic field. In addition, the exchange distance deduced from the susceptibility exponent is shown to decay as [Formula: see text]. Based on the observations, we suggest that the competition between direct magnetic exchange and Coulombic and/or RKKY interactions should be responsible for the intrinsic magnetism in this system.
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Affiliation(s)
- Qianhui Mao
- College of Science, Henan University of Engineering, Xinzheng 451191, People's Republic of China. Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China
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Critical behavior of the van der Waals bonded high T C ferromagnet Fe 3GeTe 2. Sci Rep 2017; 7:6184. [PMID: 28733606 PMCID: PMC5522457 DOI: 10.1038/s41598-017-06671-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/14/2017] [Indexed: 11/08/2022] Open
Abstract
Fe3GeTe2 is a promising candidate for van der Waals bonded ferromagnet because of its high Curie temperature and the prediction that its ferromagnetism can maintain upon exfoliating down to single layer. Here, we have reported the critical behavior to understand its ferromagnetic exchange. Based on various techniques including modified Arrott plot, Kouvel-Fisher plot, and critical isotherm analysis, a set of reliable critical exponents (β = 0.327 ± 0.003, γ = 1.079 ± 0.005, and δ = 4.261 ± 0.009) has been obtained. The critical behavior suggests a three-dimensional long-range magnetic coupling with the exchange distance decaying as J(r) ≈ r−4.6 in Fe3GeTe2. The possible origin of three-dimensional magnetic characteristics in van der Waals bonded magnets is discussed.
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Chen L, Fan J, Tong W, Hu D, Ji Y, Liu J, Zhang L, Pi L, Zhang Y, Yang H. Evolution of the intrinsic electronic phase separation in La 0.6Er 0.1Sr 0.3MnO 3 perovskite. Sci Rep 2016; 6:14. [PMID: 28442764 PMCID: PMC5431341 DOI: 10.1038/s41598-016-0009-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/15/2016] [Indexed: 11/19/2022] Open
Abstract
Magnetic and electronic transport properties of perovskite manganite La0.6Er0.1Sr0.3MnO3 have been thoroughly examined through the measurements of magnetization, electron paramagnetic resonance(EPR), and resistivity. It was found that the substitution of Er3+ for La3+ ions introduced the chemical disorder and additional strain in this sample. An extra resonance signal occurred in EPR spectra at high temperatures well above TC gives a strong evidence of electronic phase separation(EPS). The analysis of resistivity enable us to identify the polaronic transport mechanism in the paramagnetic region. At low temperature, a new ferromagnetic interaction generates in the microdomains of Er3+-disorder causing the second increase of magnetization. However, the new ferromagnetic interaction does not improve but decreases electronic transport due to the enhancement of interface resistance among neighboring domains. In view of a really wide temperature region for the EPS existence, this sample provides an ideal platform to uncover the evolution law of different magnetic structures in perovskite manganites.
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Affiliation(s)
- Lili Chen
- Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Jiyu Fan
- Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Wei Tong
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031, China
| | - Dazhi Hu
- Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Yanda Ji
- Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Jindong Liu
- Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Lei Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031, China
| | - Li Pi
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031, China
| | - Yuheng Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031, China
| | - Hao Yang
- Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
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10
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Liu B, Zou Y, Zhang L, Zhou S, Wang Z, Wang W, Qu Z, Zhang Y. Critical behavior of the quasi-two-dimensional semiconducting ferromagnet CrSiTe3. Sci Rep 2016; 6:33873. [PMID: 27649846 PMCID: PMC5030636 DOI: 10.1038/srep33873] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 09/05/2016] [Indexed: 11/10/2022] Open
Abstract
The semiconducting ferromagnet CrSiTe3 is a promising candidate for two-dimensional magnet simply by exfoliating down to single layers. To understand the magnetic behavior in thin-film samples and the possible applications, it is necessary to establish the nature of the magnetism in the bulk. In this work, the critical behavior at the paramagnetic to ferromagnetic phase transition in single-crystalline CrSiTe3 is investigated by bulk magnetization measurements. We have obtained the critical exponents (β = 0.170 ± 0.008, γ = 1.532 ± 0.001, and δ = 9.917 ± 0.008) and the critical temperature TC = 31.0 K using various techniques such as modified Arrott plot, Kouvel-Fisher plot, and critical isotherm analysis. Our analysis suggests that the determined exponents match well with those calculated from the results of renormalization group approach for a two-dimensional Ising model coupled with long-range interaction.
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Affiliation(s)
- Bingjie Liu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China.,University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Youming Zou
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Lei Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Shiming Zhou
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhe Wang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China.,University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Weike Wang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Zhe Qu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Yuheng Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China.,Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
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11
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Pramanik AK, Banerjee A. Finite-size effect on evolution of Griffiths phase in manganite nanoparticles. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:35LT02. [PMID: 27383058 DOI: 10.1088/0953-8984/28/35/35lt02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The finite-size effect on the evolution of the Griffiths phase (GP) is studied using nanoparticles of half-doped manganite Pr0.5Sr0.5MnO3 with different average particle sizes but with similar structural parameters. All the samples exhibit pronounced GP behavior. With reducing the particle size, the Griffiths temperature remains almost unchanged but the characteristic critical temperature [Formula: see text] decreases and the GP properties are strengthened. It is noteworthy that the shift of [Formula: see text] follows finite-size scaling with the particle size revealing an exotic interplay between the GP properties and the sample dimension. This reinforces an earlier proposal of length-scale related evolution of GP.
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Caballero-Flores R, Bingham NS, Phan MH, Torija MA, Leighton C, Franco V, Conde A, Phan TL, Yu SC, Srikanth H. Magnetocaloric effect and critical behavior in Pr0.5Sr0.5MnO3: an analysis of the validity of the Maxwell relation and the nature of the phase transitions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:286001. [PMID: 24945593 DOI: 10.1088/0953-8984/26/28/286001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The Maxwell relation, the Clausius-Clapeyron equation, and a non-iterative method to obtain the critical exponents have been used to characterize the magnetocaloric effect (MCE) and the nature of the phase transitions in Pr0.5Sr0.5MnO3, which undergoes a second-order paramagnetic to ferromagnetic (PM-FM) transition at TC ~ 247 K, and a first-order ferromagnetic to antiferromagnetic (FM-AFM) transition at TN ~ 165 K. We find that around the second-order PM-FM transition, the MCE (as represented by the magnetic entropy change, ΔSM) can be precisely determined from magnetization measurements using the Maxwell relation. However, around the first-order FM-AFM transition, values of ΔSM calculated with the Maxwell relation deviate significantly from those calculated by the Clausius-Clapeyron equation at the magnetic field and temperature ranges where a conversion between the AFM and FM phases occurs. A detailed analysis of the critical exponents of the second-order PM-FM transition allows us to correlate the short-range type magnetic interactions with the MCE. Using the Arrott-Noakes equation of state with the appropriate values of the critical exponents, the field- and temperature-dependent magnetization [Formula: see text] curves, and hence the [Formula: see text] curves, have been simulated and compared with experimental data. A good agreement between the experimental and simulated data has been found in the vicinity of the Curie temperature TC, but a noticeable discrepancy is present for [Formula: see text]. This discrepancy arises mainly from the coexistence of AFM and FM phases and the presence of ferromagnetic clusters in the AFM matrix.
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Affiliation(s)
- R Caballero-Flores
- Department of Physics, University of South Florida, Tampa, FL 33620, USA. Departamento de Física de la Materia Condensada, ICMSE-CSIC, Universidad de Sevilla, 41080 Sevilla, Spain. Departamento de Física, Universidad de Oviedo, 33007 Oviedo, Spain
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13
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Kundu S, Nath TK. Size-dependent electronic-transport mechanism and sign reversal of magnetoresistance in Nd0.5Sr0.5CoO3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:236005. [PMID: 22576276 DOI: 10.1088/0953-8984/24/23/236005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A detailed investigation of electronic-transport properties of Nd(0.5)Sr(0.5)CoO(3) has been carried out as a function of grain size ranging from micrometre order down to an average size of 28 nm. Interestingly, we observe a size induced metal-insulator transition in the lowest grain-size sample while the bulk-like sample is metallic in the whole measured temperature regime. An analysis of the temperature dependent resistivity in the metallic regime reveals that the electron-electron interaction is the dominating mechanism while other processes like electron-magnon and electron-phonon scatterings are also likely to be present. The fascinating observation of enhanced low temperature upturn and minimum in resistivity on reduction of grain size is found due to electron-electron interaction (quantum interference effect). This effect is attributed to enhanced disorder on reduction of grain size. Interestingly, we observe a cross over from positive to negative magnetoresistance in the low temperature regime as the grain size is reduced. This observed sign reversal is attributed to enhanced phase separation on decreasing the grain size of the cobaltite.
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Affiliation(s)
- S Kundu
- Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur, West Bengal, India.
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Thorat ND, Shinde KP, Pawar SH, Barick KC, Betty CA, Ningthoujam RS. Polyvinyl alcohol: an efficient fuel for synthesis of superparamagnetic LSMO nanoparticles for biomedical application. Dalton Trans 2012; 41:3060-71. [PMID: 22277953 DOI: 10.1039/c2dt11835a] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
La(0.7)Sr(0.3)MnO(3) (LSMO) nanoparticles have been prepared using glycine and polyvinyl alcohol (PVA) as fuels. Their crystal structure, particle morphology and compositions are characterized using X-ray diffraction, transmission electron microscopy, field-emission electron microscopy and energy dispersive analysis of X-ray. They show a pseudo-cubic perovskite structure. The spherical particle sizes of 30 and 20 nm have been obtained from samples prepared by glycine and PVA respectively. The field cooled (FC) and zero field cooled (ZFC) magnetizations have been recorded from 5 to 375 K at 500 Oe and superparamagnetic blocking temperatures (T(B)) of 75 and 30 K are obtained from samples prepared by glycine and PVA respectively. Particle size distribution is observed from dynamic light scattering measurements. Dispersion stability of the particles in water is studied by measuring the Zeta potential with varying the pH of the medium from 1 to 12. Under induction heating experiments, a hyperthermia temperature (42-43 °C) is achieved by both the samples (3-6 mg mL(-1)) at magnetic fields of 167-335 Oe and at a frequency of 267 kHz. The bio-compatibility of the LSMO nanoparticles is studied on the L929 and HeLa cell lines by MTT assay for up to 48 h. The present work reveals the importance of synthesis technique and fuel choice on structural, morphological, magnetic, hyperthermia and biocompatible properties of LSMO and predicts the suitability for biomedical applications.
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Affiliation(s)
- N D Thorat
- Center for Interdisciplinary Research, D Y Patil University, Kolhapur, India
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15
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Kundu S, Nath TK. Evidence of electronic phase arrest and glassy ferromagnetic behaviour in (Nd(0.4)Gd(0.3))Sr(0.3)MnO3 manganite: comparative study between bulk and nanometric samples. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:356001. [PMID: 21849715 DOI: 10.1088/0953-8984/23/35/356001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The effect of the doping of rare earth Gd(3+) ions replacing Nd(3+) in Nd(0.7)Sr(0.3)MnO(3) is investigated in detail. Measurements of resistivity, magnetoresistance, magnetization, and linear and nonlinear ac magnetic susceptibility on chemically synthesized (Nd(0.7-x)Gd(x))Sr(0.3)MnO(3) show various interesting features with doping level x=0.3. A comparative study has been carried out between a bulk and a nanometric sample (grain size ∼60 nm) synthesized from the same as a prepared powder to maintain an identical stoichiometry. The resistivity of the samples shows strong dependence on the magnetic field-temperature history. The magnetoresistance of the samples also shows strong irreversibility with respect to sweeping of the field between the highest positive and negative values. Moreover, the resistivity is found to increase with time after field cooling and then switching off the field. All these phenomena have been attributed to phase separation effects and the arrest of phases in the samples. Furthermore, the bulk sample displays a spin glass like behaviour as evident from the frequency dependence of linear ac magnetic susceptibility and critical divergence of the nonlinear ac magnetic susceptibility. The experimentally obtained characteristic time τ(0) after dynamical scaling analysis of the frequency dependence of the ac susceptibility is found to be 10(-17) s which implies that the system is different from a canonical spin glass. An unusual frequency dependence of the second harmonic of ac susceptibility around the magnetic transition temperature led us to designate the magnetic state of the sample to be glassy ferromagnetic. On reduction of the grain size low field magnetoresistance and phase arrest phenomena are found to enhance but the glassy state is observed to be destabilized in the nanometric sample.
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Affiliation(s)
- S Kundu
- Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur, West Bengal 721302, India.
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16
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Dhiman I, Das A, Nigam AK, Gasser U. Influence of B-site disorder in La0.5Ca0.5Mn(1 - x)B(x)O3 (B = Fe, Ru, Al and Ga) manganites. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:246006. [PMID: 21628788 DOI: 10.1088/0953-8984/23/24/246006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have investigated the influence of B-site doping on the crystal and magnetic structure in La(0.5)Ca(0.5)Mn(1 - x)B(x)O(3) (B = Fe, Ru, Al and Ga) compounds using neutron diffraction, small angle neutron scattering, magnetization and resistivity techniques. The B-site doped samples are isostructural and possess an orthorhombic structure in the Pnma space group at 300 K. A structural transition from orthorhombic to monoclinic is found to precede the magnetic transition to the CE-type antiferromagnetic state in a few of these samples. On doping with Fe, the charge and orbitally ordered CE-type antiferromagnetic state is suppressed, followed by growth of the ferromagnetic insulating phase in 0.02 ≤ x ≤ 0.06 compounds. At higher Fe doping in x > 0.06, the ferromagnetic state is also suppressed and no evidence of long range magnetic ordering is observed. In Ru doped samples (0.01 ≤ x ≤ 0.05), the ferromagnetic metallic state is favored at T(C)≈200 K and T(MI)≈125 K and no significant change in T(C) and T(MI) as a function of Ru doping is found. In contrast, with non-magnetic Al substitution for 0.01 ≤ x ≤ 0.03, the charge ordered CE-type antiferromagnetic state coexists with the ferromagnetic metallic phase. With further increase in Al doping (0.05 ≤ x ≤ 0.07), both CE-type antiferromagnetic and ferromagnetic phases are gradually suppressed. This behavior is accompanied by the evolution of an A-type antiferromagnetic insulating state. Eventually, at higher Al doping (0.10 ≤ x ≤ 0.13), this phase is also suppressed and the signature of a spin glass like transition is evident in M(T). Likewise, substitution with Ga is observed to induce similar effects to those described for Al doped samples. The presence of short ranged ferromagnetic ordering has been further explored using small angle neutron scattering measurements in a few of the selected samples.
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Affiliation(s)
- Indu Dhiman
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, India
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Mukherjee K, Banerjee A. Selective substitution in orbital domains of a low doped manganite: an investigation from Griffiths phenomenon and modification of glassy features. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:106001. [PMID: 21817440 DOI: 10.1088/0953-8984/21/10/106001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An effort is made to study the contrast in magnetic behavior resulting from minimal disorder introduced by substitution of 2.5% Ga or Al in Mn site of La(0.9)Sr(0.1)MnO(3). It is considered that Ga or Al selectively create disorder within the orbital domains or on its walls, causing enhancement of Griffiths phase (GP) singularity for the former and disappearance of it in the latter case. It is shown that Ga replaces Mn(3+), which is considered to be concentrated within the domains, whereas Al replaces Mn(4+), which is segregated on the hole-rich walls, without causing any significant effect on structure or ferromagnetic transition temperatures. Thus, it is presumed that the effect of disorder created by Ga extends across the bulk of the domain having correlation over a similar length scale, resulting in enhancement of the GP phenomenon. In contrast, the effect of disorder created by Al remains restricted to the walls, resulting in the modification of the dynamics arising from the domain walls and suppresses the GP. Moreover, contrasting features are observed in the low temperature region of the compounds; a re-entrant spin-glass-like behavior is observed in the Ga-doped sample, while the observed characteristics for the Al-doped sample are ascribed only to modified domain wall dynamics with the absence of any glassy phase. Distinctive features in third-order susceptibility measurements reveal that the magnetic ground state of the entire series comprises of orbital domain states. These observations bring out the role of the nature of disorder on the GP phenomenon and also reconfirms the character of self-organization in low doped manganites.
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Affiliation(s)
- K Mukherjee
- UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017, MP, India
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