Abstract
Alternative explanation to the effect of disappearance of the Morin transition on hematite nanoparticles with their size decreasing is proposed basing on an idea of the predominant role of the shape anisotropy for nanosize particles. Three types of the magnetic structure of hematite nanoparticles with various sizes are found by Mössbauer spectroscopy: coexistence of the well-pronounced antiferromagnetic and weakly ferromagnetic phases for particles with average diameters of about 55 nm, non-uniform distribution of the magnetization axes which concentrate on the vicinity of the basal plane (111) for prolonged particles with cross sections of about 20 nm, and uniform distribution of the easy axes in regard to the crystalline directions for 3-nm particles. Description of the temperature evolution of experimental data within novel model of the magnetic dynamics for antiferromagnetic particles which accounts the exchange, relativistic, and anisotropy interactions is provided, and the structural as well as energy characteristics of the studied systems are reconstructed.
Similar content being viewed by others
References
Afanas’ev AM, Chuev MA (1995) Discrete forms of Mössbauer spectra. JETP 80(3):560–567
Bødker F, Hansen MF, Koch CB, Lefmann K, Mørup S (2000) Magnetic properties of hematite nanoparticles. Phys Rev B 61(10):6826–6838
Bordonali L et al (2012) 1H-NMR study of the spin dynamics of fine superparamagnetic nanoparticles. Phys Rev B 85(7):174426
Chuev MA (2011) Multi-level relaxation model for describing the Mössbauer spectra of single-domain particles in the presence of quadrupolar hyperfine interaction. J Phys Condens Matter 23(11):426003
Chuev MA (2012) On the thermodynamics of antiferromagnetic nanoparticles by example of Mössbauer spectroscopy. JETP Lett 95(6):295–301
Chuev MA (2014) Macroscopic quantum effects observed in Mössbauer spectra of antiferromagnetic nanoparticles. Hyperfine Interact 226:111–122
Chuev MA (2016) Nutations of magnetization of sublattices and their role in the formation of Mössbauer spectra of antiferromagnetic nanoparticles. JETP Lett 103(3):175–180
Chuev MA (2017) Excitation spectrum of the Néel ensemble of antiferromagnetic nanoparticles as revealed in Mössbauer spectroscopy. Adv Condens Matter Phys 2017(15):6209206
Chuev MA, Hesse J (2009) Non-equilibrium magnetism of single-domain particles for characterization of magnetic nanomaterials. In: Tamayo KB (ed) Magnetic properties of solids. Nova Science, New York, pp 1–104
Chuev MA, Mishchenko IN, Kubrin SP, Lastovina TA (2017) Novel insight into the effect of disappearance of the Morin transition in hematite nanoparticles. JETP Lett 105(11):700–705
Dzyaloshinskii IE (1957) Thermodynamic theory of “weak” ferromagnetism in antiferromagnetic substances. Sov Phys JETP 5:1259–1272
Jones DH, Srivastava KKP (1986) Many-state relaxation model for the Mössbauer spectra of superparamagnets. Phys Rev B 34(11):7542–7548
Kündig W, Bömmel H, Constabaris G, Lindquist RH (1966) Some properties of supported small α-Fe2O3 particles determined with the Mössbauer effect. Phys Rev 142(2):327–333
Mischenko I, Chuev M (2016) Quantum-mechanical and continual models of magnetic dynamics for antiferromagnetic particles in Mössbauer spectra analysis. Hyperfine Interact 237(21):1–11
Mischenko I, Chuev M, Cherepanov V, Polikarpov M (2014) Antiferromagnetic fluctuations in CePdSn Kondo compound from Mössbauer spectroscopy. Hyperfine Interact 226:299–308
Morin FJ (1950) Magnetic susceptibility of α-Fe2O3 and α-Fe2O3 with added titanium. Phys Rev 78:819–820
Moriya T (1960) Anisotropic superexchange interaction and weak ferromagnetism. Phys Rev 120(1):91–98
Özdemir Ö, Dunlop DJ, Berquó TS (2008) Morin transition in hematite: size dependence and thermal hysteresis. Geochem Geophys Geosyst 9(10):1–12
Rancourt DG (1989) Accurate site populations from Mössbauer spectroscopy. Nucl Instr Meth Phys Res B 44:199–210
van der Woude F (1966) Mössbauer effect in α-Fe2O3. Phys Status Solidi 17:417–432 www.alfa.com/en/catalog/047044
Acknowledgments
Authors thank Prof. J. Litterst and Dr. M. Kracken at the Technical University of Braunschweig for the experimental spectra of dextran-coated nanoparticles.
Funding
Experimental part of this work (section “Samples and experiment”) was supported by the Russian Ministry for Education and Science, project no. 14.587.21.0027. Theoretical and calculation part (section “Results of analysis”) was carried out under Program of Federal Agency for Scientific Organizations of Russia.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Rights and permissions
About this article
Cite this article
Mishchenko, I., Chuev, M., Kubrin, S. et al. Continual model of magnetic dynamics for antiferromagnetic particles in analyzing size effects on Morin transition in hematite nanoparticles. J Nanopart Res 20, 141 (2018). https://doi.org/10.1007/s11051-018-4248-9
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s11051-018-4248-9