Sub-lattice of Jahn-Teller centers in hexaferrite crystal

Гудков, В. В.; Сарычев, М. Н.; Жерлицын, С.; Жевстовских, И. В.; Аверкиев, Н. С.; Винник, Д.А.; Gudkova, S.A.; Niewa, Rainer; Dressel, Martin; Alyabyeva, Liudmila; Gorshunov, B. P.; Берсукер, И. Б.

doi:10.1038/s41598-020-63915-7

Cited by 29 publications

(24 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As one alternative explanation, a sublattice of Jahn-Teller centers, if found, could in principle be connected to transport and relaxation of magnetism. Such a sublattice has been identified in Titanium-doped hexaferrite [25] with structural relaxations present in a similar temperature interval and activation energies comparable to our findings. Also, magnetic aftereffect measurements in hexaferrites provide evidence of Fe 2+ ion diffusion [8] which might influence transport via hopping between Fe 2+ sites [10].…”

Section: Discussionsupporting

confidence: 90%

Persisting correlation between electrical transport and magnetic dynamics in M-type hexaferrites

Rapljenović¹,

Novosel²,

Dominko³

et al. 2021

Preprint

View full text Add to dashboard Cite

In this work we present frequency-dependent magnetic susceptibility and dc electric transport properties of three different compositions of hexaferrite Ba 1−x -Pb x Fe 12−y Al y O 19 . We find a correlation between activation energies of dc electric transport and ac magnetic susceptibility which persists in the whole researched range of aluminium substitution x = 0 to 3.3. This result is discussed in the context of charged magnetic domain walls, the pinning of which is determined by charge carriers activated over the transport gap. Our work points toward a general relaxational mechanism in ferrimagnetic semiconductors which directly affects dynamic magnetic properties via electric transport.

show abstract

Section: Discussionsupporting

confidence: 90%

Persisting correlation between electrical transport and magnetic dynamics in M-type hexaferrites

Rapljenović¹,

Novosel²,

Dominko³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…As mentioned in Section 3, the knowledge that the distorted configurations of polyatomic systems are due to (and only to) the JTE or PJTE, is important by itself, even when they are from the third group of systems in the above classification with very large τ values. Indeed, this knowledge allows manipulating the structure and properties of such systems by means of external perturbations, targeting the JTE or PJTE parameters [23][24][25]. Such manipulations were realized in a series of two-dimensional systems with puckered or buckled out-of-plane distortions induced by the PJTE, by restoring their planar configuration with external influence [23,24], and in some hexaferrite crystals, by creating a sublattice of JTE centers via changing their oxidation state with redox dopants [25].…”

Section: Experimental Observation Of Spontaneous Symmetry Breaking the Curie Principlementioning

confidence: 99%

“…Indeed, this knowledge allows manipulating the structure and properties of such systems by means of external perturbations, targeting the JTE or PJTE parameters [23][24][25]. Such manipulations were realized in a series of two-dimensional systems with puckered or buckled out-of-plane distortions induced by the PJTE, by restoring their planar configuration with external influence [23,24], and in some hexaferrite crystals, by creating a sublattice of JTE centers via changing their oxidation state with redox dopants [25].…”

Section: Experimental Observation Of Spontaneous Symmetry Breaking the Curie Principlementioning

confidence: 99%

The Jahn–Teller and Pseudo-Jahn–Teller Effects: A Unique and Only Source of Spontaneous Symmetry Breaking in Atomic Matter

Берсукер

2021

Symmetry

View full text Add to dashboard Cite

In a mostly review paper, we show that the important problem of symmetry, broken symmetry, and spontaneous broken symmetry of polyatomic systems is directly related to the Jahn–Teller (JT) and pseudo-Jahn–Teller (PJT) effects, including the hidden-JT and hidden-PJT effects, and these JT effects (JTEs) are the only source of spontaneous symmetry breaking in matter. They are directly related to the violation of the adiabatic approximation by the vibronic and other nonadiabatic couplings (jointly termed nonadiabaticity) in the interaction between the electrons and nuclei, which becomes significant in the presence of two or more degenerate or pseudodegenerate electronic states. In a generalization of this understanding of symmetry, we suggest an improved (quantum) definition of stereo-chemical polyatomic space configuration, in which, starting with their high-symmetry configuration, we separate all atomic systems into three distinguishable groups: (1) weak nonadiabaticity, stable high-symmetry configurations; (2) moderate-to-strong nonadiabaticity, unstable high-symmetry configurations, JTEs, spontaneous symmetry breaking (SSB); (3) very strong nonadiabaticity, stable distorted configurations. The JTEs, inherent to the second group of systems, produce a rich variety of novel properties, based on their multiminimum adiabatic potential energy surface (APES), leading to a short lifetime in the distorted configuration. We show the role of the Curie principle in the possibilities to observe the SSB in atomic matter, and mention briefly the revealed recently gamma of novel properties of matter in its interaction with external perturbation that occur due to the SSB, including ferroelectricity and orientational polarization, leading to enhanced permittivity and flexoelectricity.

show abstract

“…Before discussing the behavior and the origin of the soft excitation in more detail, we comment on four narrower absorption lines that are resolved at the lowest temperatures on the highfrequency wing of the excitation; they are marked by arrows in Fig. 1 20 , calculations of the adiabatic potential showed that for Fe 2+ in BaM matrix, it is the tetrahedral coordination that is most energetically favorable. We note that the intensities of the lines are higher in the x=0.2 Ba 1-x Pb x Fe 12 O 19 compound compared to the compound with x=0.1, which is in agreement with our assumption on the nature of these absorption lines due to the presence of the Pb 2+ ions.…”

Section: Thz Spectra the Soft Modementioning

confidence: 99%

“…Functional characteristics of substituted hexaferrites show an outstanding sensitivity to doping, making these materials the future candidates for novel devices of THz optoelectronics. Doped M-type hexaferrites exhibit superior magnetic characteristics, including the ferromagnetic resonance frequency located in the THz range, record values of the coercive force of up to 40 kOe 19 , and formation of a new type of Jahn-Teller sub-lattice 20 . Doping BaM with lead is expected to systematically change its dielectric properties.…”

Section: Introductionmentioning

confidence: 99%

Lead-substituted barium hexaferrite for tunable terahertz optoelectronics

Alyabyeva

Prokhorov

Винник

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

In recent years, due to their outstanding dielectric and magnetic properties, hexagonal ferrites (hexaferrites) have attracted considerable interest for developing electronic components of next-generation communication systems. The complex crystal structure of hexaferrites and critical dependences of their electric and magnetic properties on external factors, like magnetic or electric fields, pressure or doping, open ample opportunities for targeted tuning of these properties when designing specific devices. To that end, we explored the electromagnetic properties of the Pb-substituted barium hexaferrite, Ba1-xPbxFe12O19, a compound featuring an extremely rich set of physical phenomena that are inherent in the dielectric and magnetic subsystems of the material and are expected to have significant effect on its electromagnetic response at radio and terahertz frequencies. We performed the first detailed measurements of the AC response of single-crystalline Ba1-xPbxFe12O19 in an extremely broad spectral range from 1 Hz to 240 THz down to temperatures as low as 5 K. We fully characterized numerous microscopic phenomena that determine the broad-band dielectric response of the compound, and we analyzed their nature. This includes temperature-activated radiofrequency relaxations that were attributed to the dynamic response of magnetic/dielectric domains. The terahertz response is dominated by a ferroelectric-like soft mode with an unusual temperature behavior that we explain by means of a microscopic model. Several narrower terahertz excitations are associated with electronic transitions between the fine-structure components of the Fe2+ground state. Narrow resonances detected in the gigahertz region are presumably of magneto-electric origin. The obtained data on diverse but controllable electromagnetic properties of Ba1-xPbxFe12O19 compounds provides the researchers with information that makes the entire class of hexaferrites materials attractive for manufacturing electronic devices for the radiofrequency and terahertz ranges, such as absorbing coatings, anti-reflective coatings, absorbers, electromagnetic shields, antennas, phase shifters, filters, resonators, modulators, etc.

show abstract

Sub-lattice of Jahn-Teller centers in hexaferrite crystal

Cited by 29 publications

References 65 publications

Persisting correlation between electrical transport and magnetic dynamics in M-type hexaferrites

Persisting correlation between electrical transport and magnetic dynamics in M-type hexaferrites

The Jahn–Teller and Pseudo-Jahn–Teller Effects: A Unique and Only Source of Spontaneous Symmetry Breaking in Atomic Matter

Lead-substituted barium hexaferrite for tunable terahertz optoelectronics

Contact Info

Product

Resources

About